Positioning model failure detection

ABSTRACT

In an aspect, a method of wireless communication performed by a user equipment (UE) includes determining that a positioning model error instance has occurred during a positioning occasion based on 1) a position uncertainty associated with a first position estimate satisfying positioning uncertainty error criteria, wherein the first position estimate is obtained during the positioning occasion by applying a first positioning model to radio frequency fingerprint (RFFP) measurements, 2) a positioning mismatch between the first position estimate of the UE and a second position estimate of the UE satisfying position mismatch error criteria, wherein the second position estimate of the UE is obtained during the positioning occasion by performing a positioning technique that does not use the first positioning model, or 3) any combination thereof; and determining that the first positioning model has failed based on a number of positioning model error instances satisfying positioning model failure criteria.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

Aspects of the disclosure relate generally to wireless communications.

2. Description of the Related Art

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G and 2.75G networks), a third-generation (3G) high speeddata, Internet-capable wireless service and a fourth-generation (4G)service (e.g., Long Term Evolution (LTE) or WiMax). There are presentlymany different types of wireless communication systems in use, includingcellular and personal communications service (PCS) systems. Examples ofknown cellular systems include the cellular analog advanced mobile phonesystem (AMPS), and digital cellular systems based on code divisionmultiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), the Global System for Mobilecommunications (GSM), etc.

A fifth generation (5G) wireless standard, referred to as New Radio(NR), enables higher data transfer speeds, greater numbers ofconnections, and better coverage, among other improvements. The 5Gstandard, according to the Next Generation Mobile Networks Alliance, isdesigned to provide higher data rates as compared to previous standards,more accurate positioning (e.g., based on reference signals forpositioning (RS-P), such as downlink, uplink, or sidelink positioningreference signals (PRS)), and other technical enhancements. Theseenhancements, as well as the use of higher frequency bands, advances inPRS processes and technology, and high-density deployments for 5G,enable highly accurate 5G-based positioning.

SUMMARY

The following presents a simplified summary relating to one or moreaspects disclosed herein. Thus, the following summary should not beconsidered an extensive overview relating to all contemplated aspects,nor should the following summary be considered to identify key orcritical elements relating to all contemplated aspects or to delineatethe scope associated with any particular aspect. Accordingly, thefollowing summary has the sole purpose to present certain conceptsrelating to one or more aspects relating to the mechanisms disclosedherein in a simplified form to precede the detailed descriptionpresented below.

In an aspect, a method of wireless communication performed by a userequipment (UE) includes determining that a positioning model errorinstance has occurred during a positioning occasion based on 1) aposition uncertainty associated with a first position estimatesatisfying positioning uncertainty error criteria, wherein the firstposition estimate is obtained during the positioning occasion byapplying a first positioning model to radio frequency fingerprint (RFFP)measurements, 2) a positioning mismatch between the first positionestimate of the UE and a second position estimate of the UE satisfyingposition mismatch error criteria, wherein the second position estimateof the UE is obtained during the positioning occasion by performing apositioning technique that does not use the first positioning model, or3) any combination thereof; and determining that the first positioningmodel has failed based on a number of positioning model error instancessatisfying positioning model failure criteria.

In an aspect, a user equipment (UE) includes a memory; at least onetransceiver; and at least one processor communicatively coupled to thememory and the at least one transceiver, the at least one processorconfigured to: determine that a positioning model error instance hasoccurred during a positioning occasion based on 1) a positionuncertainty associated with a first position estimate satisfyingpositioning uncertainty error criteria, wherein the first positionestimate is obtained during the positioning occasion by applying a firstpositioning model to radio frequency fingerprint (RFFP) measurements, 2)a positioning mismatch between the first position estimate of the UE anda second position estimate of the UE satisfying position mismatch errorcriteria, wherein the second position estimate of the UE is obtainedduring the positioning occasion by performing a positioning techniquethat does not use the first positioning model, or 3) any combinationthereof; and determine that the first positioning model has failed basedon a number of positioning model error instances satisfying positioningmodel failure criteria.

In an aspect, a user equipment (UE) includes means for determining thata positioning model error instance has occurred during a positioningoccasion based on 1) a position uncertainty associated with a firstposition estimate satisfying positioning uncertainty error criteria,wherein the first position estimate is obtained during the positioningoccasion by applying a first positioning model to radio frequencyfingerprint (RFFP) measurements, 2) a positioning mismatch between thefirst position estimate of the UE and a second position estimate of theUE satisfying position mismatch error criteria, wherein the secondposition estimate of the UE is obtained during the positioning occasionby performing a positioning technique that does not use the firstpositioning model, or 3) any combination thereof; and means fordetermining that the first positioning model has failed based on anumber of positioning model error instances satisfying positioning modelfailure criteria.

In an aspect, a non-transitory computer-readable medium storescomputer-executable instructions that, when executed by a user equipment(UE), cause the UE to: determine that a positioning model error instancehas occurred during a positioning occasion based on 1) a positionuncertainty associated with a first position estimate satisfyingpositioning uncertainty error criteria, wherein the first positionestimate is obtained during the positioning occasion by applying a firstpositioning model to radio frequency fingerprint (RFFP) measurements, 2)a positioning mismatch between the first position estimate of the UE anda second position estimate of the UE satisfying position mismatch errorcriteria, wherein the second position estimate of the UE is obtainedduring the positioning occasion by performing a positioning techniquethat does not use the first positioning model, or 3) any combinationthereof; and determine that the first positioning model has failed basedon a number of positioning model error instances satisfying positioningmodel failure criteria.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description ofvarious aspects of the disclosure and are provided solely forillustration of the aspects and not limitation thereof.

FIG. 1 illustrates an example wireless communications system, accordingto aspects of the disclosure.

FIGS. 2A, 2B, and 2C illustrate example wireless network structures,according to aspects of the disclosure.

FIGS. 3A, 3B, and 3C are simplified block diagrams of several sampleaspects of components that may be employed in a user equipment (UE), abase station, and a network entity, respectively, and configured tosupport communications as taught herein.

FIG. 4 illustrates examples of various positioning methods supported inNew Radio (NR), according to aspects of the disclosure.

FIG. 5 is a diagram illustrating an example frame structure, accordingto aspects of the disclosure.

FIG. 6 is a graph representing a radio frequency (RF) channel estimate,according to aspects of the disclosure.

FIG. 7 illustrates an example neural network, according to aspects ofthe disclosure.

FIG. 8 is a diagram illustrating the use of a machine learning (ML)model for RF fingerprinting (RFFP)-based positioning, according toaspects of the disclosure.

FIG. 9 is a diagram illustrating the inference cycle for UE-baseddownlink RFFP (DL-RFFP) positioning, according to aspects of thedisclosure.

FIG. 10 illustrates an example call flow for UE-based DL-RFFPpositioning, according to aspects of the disclosure.

FIG. 11 is a timing diagram showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances, according to aspects of the disclosure.

FIG. 12 is a timing diagram showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances occurring over a specified time duration, according to aspectsof the disclosure.

FIG. 13 is a timing diagram showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances occurring over a specified time duration, according to aspectsof the disclosure.

FIG. 14 illustrates an example method of wireless communicationperformed by a UE, according to aspects of the disclosure.

DETAILED DESCRIPTION

Aspects of the disclosure are provided in the following description andrelated drawings directed to various examples provided for illustrationpurposes. Alternate aspects may be devised without departing from thescope of the disclosure. Additionally, well-known elements of thedisclosure will not be described in detail or will be omitted so as notto obscure the relevant details of the disclosure.

The words “exemplary” and/or “example” are used herein to mean “servingas an example, instance, or illustration.” Any aspect described hereinas “exemplary” and/or “example” is not necessarily to be construed aspreferred or advantageous over other aspects. Likewise, the term“aspects of the disclosure” does not require that all aspects of thedisclosure include the discussed feature, advantage or mode ofoperation.

Those of skill in the art will appreciate that the information andsignals described below may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the description below may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof, depending inpart on the particular application, in part on the desired design, inpart on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions tobe performed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits (e.g., application specific integrated circuits(ASICs)), by program instructions being executed by one or moreprocessors, or by a combination of both. Additionally, the sequence(s)of actions described herein can be considered to be embodied entirelywithin any form of non-transitory computer-readable storage mediumhaving stored therein a corresponding set of computer instructions that,upon execution, would cause or instruct an associated processor of adevice to perform the functionality described herein. Thus, the variousaspects of the disclosure may be embodied in a number of differentforms, all of which have been contemplated to be within the scope of theclaimed subject matter. In addition, for each of the aspects describedherein, the corresponding form of any such aspects may be describedherein as, for example, “logic configured to” perform the describedaction.

As used herein, the terms “user equipment” (UE) and “base station” arenot intended to be specific or otherwise limited to any particular radioaccess technology (RAT), unless otherwise noted. In general, a UE may beany wireless communication device (e.g., a mobile phone, router, tabletcomputer, laptop computer, consumer asset locating device, wearable(e.g., smartwatch, glasses, augmented reality (AR)/virtual reality (VR)headset, etc.), vehicle (e.g., automobile, motorcycle, bicycle, etc.),Internet of Things (IoT) device, etc.) used by a user to communicateover a wireless communications network. A UE may be mobile or may (e.g.,at certain times) be stationary, and may communicate with a radio accessnetwork (RAN). As used herein, the term “UE” may be referred tointerchangeably as an “access terminal” or “AT,” a “client device,” a“wireless device,” a “subscriber device,” a “subscriber terminal,” a“subscriber station,” a “user terminal” or “UT,” a “mobile device,” a“mobile terminal,” a “mobile station,” or variations thereof. Generally,UEs can communicate with a core network via a RAN, and through the corenetwork the UEs can be connected with external networks such as theInternet and with other UEs. Of course, other mechanisms of connectingto the core network and/or the Internet are also possible for the UEs,such as over wired access networks, wireless local area network (WLAN)networks (e.g., based on the Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 specification, etc.) and so on.

A base station may operate according to one of several RATs incommunication with UEs depending on the network in which it is deployed,and may be alternatively referred to as an access point (AP), a networknode, a NodeB, an evolved NodeB (eNB), a next generation eNB (ng-eNB), aNew Radio (NR) Node B (also referred to as a gNB or gNodeB), etc. A basestation may be used primarily to support wireless access by UEs,including supporting data, voice, and/or signaling connections for thesupported UEs. In some systems a base station may provide purely edgenode signaling functions while in other systems it may provideadditional control and/or network management functions.

A communication link through which UEs can send signals to a basestation is called an uplink (UL) channel (e.g., a reverse trafficchannel, a reverse control channel, an access channel, etc.). Acommunication link through which the base station can send signals toUEs is called a downlink (DL) or forward link channel (e.g., a pagingchannel, a control channel, a broadcast channel, a forward trafficchannel, etc.). As used herein the term traffic channel (TCH) can referto either an uplink/reverse or downlink/forward traffic channel.

The term “base station” may refer to a single physicaltransmission-reception point (TRP) or to multiple physical TRPs that mayor may not be co-located. For example, where the term “base station”refers to a single physical TRP, the physical TRP may be an antenna ofthe base station corresponding to a cell (or several cell sectors) ofthe base station. Where the term “base station” refers to multipleco-located physical TRPs, the physical TRPs may be an array of antennas(e.g., as in a multiple-input multiple-output (MIMO) system or where thebase station employs beamforming) of the base station. Where the term“base station” refers to multiple non-co-located physical TRPs, thephysical TRPs may be a distributed antenna system (DAS) (a network ofspatially separated antennas connected to a common source via atransport medium) or a remote radio head (RRH) (a remote base stationconnected to a serving base station). Alternatively, the non-co-locatedphysical TRPs may be the serving base station receiving the measurementreport from the UE and a neighbor base station whose reference radiofrequency (RF) signals the UE is measuring. Because a TRP is the pointfrom which a base station transmits and receives wireless signals, asused herein, references to transmission from or reception at a basestation are to be understood as referring to a particular TRP of thebase station.

In some implementations that support positioning of UEs, a base stationmay not support wireless access by UEs (e.g., may not support data,voice, and/or signaling connections for UEs), but may instead transmitreference signals to UEs to be measured by the UEs, and/or may receiveand measure signals transmitted by the UEs. Such a base station may bereferred to as a positioning beacon (e.g., when transmitting signals toUEs) and/or as a location measurement unit (e.g., when receiving andmeasuring signals from UEs).

An “RF signal” comprises an electromagnetic wave of a given frequencythat transports information through the space between a transmitter anda receiver. As used herein, a transmitter may transmit a single “RFsignal” or multiple “RF signals” to a receiver. However, the receivermay receive multiple “RF signals” corresponding to each transmitted RFsignal due to the propagation characteristics of RF signals throughmultipath channels. The same transmitted RF signal on different pathsbetween the transmitter and receiver may be referred to as a “multipath”RF signal. As used herein, an RF signal may also be referred to as a“wireless signal” or simply a “signal” where it is clear from thecontext that the term “signal” refers to a wireless signal or an RFsignal.

FIG. 1 illustrates an example wireless communications system 100,according to aspects of the disclosure. The wireless communicationssystem 100 (which may also be referred to as a wireless wide areanetwork (WWAN)) may include various base stations 102 (labeled “BS”) andvarious UEs 104. The base stations 102 may include macro cell basestations (high power cellular base stations) and/or small cell basestations (low power cellular base stations). In an aspect, the macrocell base stations may include eNBs and/or ng-eNBs where the wirelesscommunications system 100 corresponds to an LTE network, or gNBs wherethe wireless communications system 100 corresponds to a NR network, or acombination of both, and the small cell base stations may includefemtocells, picocells, microcells, etc.

The base stations 102 may collectively form a RAN and interface with acore network 170 (e.g., an evolved packet core (EPC) or a 5G core (5GC))through backhaul links 122, and through the core network 170 to one ormore location servers 172 (e.g., a location management function (LMF) ora secure user plane location (SUPL) location platform (SLP)). Thelocation server(s) 172 may be part of core network 170 or may beexternal to core network 170. A location server 172 may be integratedwith a base station 102. A UE 104 may communicate with a location server172 directly or indirectly. For example, a UE 104 may communicate with alocation server 172 via the base station 102 that is currently servingthat UE 104. A UE 104 may also communicate with a location server 172through another path, such as via an application server (not shown), viaanother network, such as via a wireless local area network (WLAN) accesspoint (AP) (e.g., AP 150 described below), and so on. For signalingpurposes, communication between a UE 104 and a location server 172 maybe represented as an indirect connection (e.g., through the core network170, etc.) or a direct connection (e.g., as shown via direct connection128), with the intervening nodes (if any) omitted from a signalingdiagram for clarity.

In addition to other functions, the base stations 102 may performfunctions that relate to one or more of transferring user data, radiochannel ciphering and deciphering, integrity protection, headercompression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, RAN sharing, multimediabroadcast multicast service (MBMS), subscriber and equipment trace, RANinformation management (RIM), paging, positioning, and delivery ofwarning messages. The base stations 102 may communicate with each otherdirectly or indirectly (e.g., through the EPC/5GC) over backhaul links134, which may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. In an aspect, one or more cellsmay be supported by a base station 102 in each geographic coverage area110. A “cell” is a logical communication entity used for communicationwith a base station (e.g., over some frequency resource, referred to asa carrier frequency, component carrier, carrier, band, or the like), andmay be associated with an identifier (e.g., a physical cell identifier(PCI), an enhanced cell identifier (ECI), a virtual cell identifier(VCI), a cell global identifier (CGI), etc.) for distinguishing cellsoperating via the same or a different carrier frequency. In some cases,different cells may be configured according to different protocol types(e.g., machine-type communication (MTC), narrowband IoT (NB-IoT),enhanced mobile broadband (eMBB), or others) that may provide access fordifferent types of UEs. Because a cell is supported by a specific basestation, the term “cell” may refer to either or both of the logicalcommunication entity and the base station that supports it, depending onthe context. In addition, because a TRP is typically the physicaltransmission point of a cell, the terms “cell” and “TRP” may be usedinterchangeably. In some cases, the term “cell” may also refer to ageographic coverage area of a base station (e.g., a sector), insofar asa carrier frequency can be detected and used for communication withinsome portion of geographic coverage areas 110.

While neighboring macro cell base station 102 geographic coverage areas110 may partially overlap (e.g., in a handover region), some of thegeographic coverage areas 110 may be substantially overlapped by alarger geographic coverage area 110. For example, a small cell basestation 102′ (labeled “SC” for “small cell”) may have a geographiccoverage area 110′ that substantially overlaps with the geographiccoverage area 110 of one or more macro cell base stations 102. A networkthat includes both small cell and macro cell base stations may be knownas a heterogeneous network. A heterogeneous network may also includehome eNBs (HeNBs), which may provide service to a restricted group knownas a closed subscriber group (CSG).

The communication links 120 between the base stations 102 and the UEs104 may include uplink (also referred to as reverse link) transmissionsfrom a UE 104 to a base station 102 and/or downlink (DL) (also referredto as forward link) transmissions from a base station 102 to a UE 104.The communication links 120 may use MIMO antenna technology, includingspatial multiplexing, beamforming, and/or transmit diversity. Thecommunication links 120 may be through one or more carrier frequencies.Allocation of carriers may be asymmetric with respect to downlink anduplink (e.g., more or less carriers may be allocated for downlink thanfor uplink).

The wireless communications system 100 may further include a wirelesslocal area network (WLAN) access point (AP) 150 in communication withWLAN stations (STAs) 152 via communication links 154 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may performa clear channel assessment (CCA) or listen before talk (LBT) procedureprior to communicating in order to determine whether the channel isavailable.

The small cell base station 102′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 102′ may employ LTE or NRtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 150. The small cell base station 102′, employing LTE/5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. NR in unlicensed spectrum maybe referred to as NR-U. LTE in an unlicensed spectrum may be referred toas LTE-U, licensed assisted access (LAA), or MulteFire.

The wireless communications system 100 may further include a millimeterwave (mmW) base station 180 that may operate in mmW frequencies and/ornear mmW frequencies in communication with a UE 182. Extremely highfrequency (EHF) is part of the RF in the electromagnetic spectrum. EHFhas a range of 30 GHz to 300 GHz and a wavelength between 1 millimeterand 10 millimeters. Radio waves in this band may be referred to as amillimeter wave. Near mmW may extend down to a frequency of 3 GHz with awavelength of 100 millimeters. The super high frequency (SHF) bandextends between 3 GHz and 30 GHz, also referred to as centimeter wave.Communications using the mmW/near mmW radio frequency band have highpath loss and a relatively short range. The mmW base station 180 and theUE 182 may utilize beamforming (transmit and/or receive) over a mmWcommunication link 184 to compensate for the extremely high path lossand short range. Further, it will be appreciated that in alternativeconfigurations, one or more base stations 102 may also transmit usingmmW or near mmW and beamforming. Accordingly, it will be appreciatedthat the foregoing illustrations are merely examples and should not beconstrued to limit the various aspects disclosed herein.

Transmit beamforming is a technique for focusing an RF signal in aspecific direction. Traditionally, when a network node (e.g., a basestation) broadcasts an RF signal, it broadcasts the signal in alldirections (omni-directionally). With transmit beamforming, the networknode determines where a given target device (e.g., a UE) is located(relative to the transmitting network node) and projects a strongerdownlink RF signal in that specific direction, thereby providing afaster (in terms of data rate) and stronger RF signal for the receivingdevice(s). To change the directionality of the RF signal whentransmitting, a network node can control the phase and relativeamplitude of the RF signal at each of the one or more transmitters thatare broadcasting the RF signal. For example, a network node may use anarray of antennas (referred to as a “phased array” or an “antennaarray”) that creates a beam of RF waves that can be “steered” to pointin different directions, without actually moving the antennas.Specifically, the RF current from the transmitter is fed to theindividual antennas with the correct phase relationship so that theradio waves from the separate antennas add together to increase theradiation in a desired direction, while cancelling to suppress radiationin undesired directions.

Transmit beams may be quasi-co-located, meaning that they appear to thereceiver (e.g., a UE) as having the same parameters, regardless ofwhether or not the transmitting antennas of the network node themselvesare physically co-located. In NR, there are four types ofquasi-co-location (QCL) relations. Specifically, a QCL relation of agiven type means that certain parameters about a second reference RFsignal on a second beam can be derived from information about a sourcereference RF signal on a source beam. Thus, if the source reference RFsignal is QCL Type A, the receiver can use the source reference RFsignal to estimate the Doppler shift, Doppler spread, average delay, anddelay spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type B, the receivercan use the source reference RF signal to estimate the Doppler shift andDoppler spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type C, the receivercan use the source reference RF signal to estimate the Doppler shift andaverage delay of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type D, the receivercan use the source reference RF signal to estimate the spatial receiveparameter of a second reference RF signal transmitted on the samechannel.

In receive beamforming, the receiver uses a receive beam to amplify RFsignals detected on a given channel. For example, the receiver canincrease the gain setting and/or adjust the phase setting of an array ofantennas in a particular direction to amplify (e.g., to increase thegain level of) the RF signals received from that direction. Thus, when areceiver is said to beamform in a certain direction, it means the beamgain in that direction is high relative to the beam gain along otherdirections, or the beam gain in that direction is the highest comparedto the beam gain in that direction of all other receive beams availableto the receiver. This results in a stronger received signal strength(e.g., reference signal received power (RSRP), reference signal receivedquality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) ofthe RF signals received from that direction.

Transmit and receive beams may be spatially related. A spatial relationmeans that parameters for a second beam (e.g., a transmit or receivebeam) for a second reference signal can be derived from informationabout a first beam (e.g., a receive beam or a transmit beam) for a firstreference signal. For example, a UE may use a particular receive beam toreceive a reference downlink reference signal (e.g., synchronizationsignal block (SSB)) from a base station. The UE can then form a transmitbeam for sending an uplink reference signal (e.g., sounding referencesignal (SRS)) to that base station based on the parameters of thereceive beam.

Note that a “downlink” beam may be either a transmit beam or a receivebeam, depending on the entity forming it. For example, if a base stationis forming the downlink beam to transmit a reference signal to a UE, thedownlink beam is a transmit beam. If the UE is forming the downlinkbeam, however, it is a receive beam to receive the downlink referencesignal. Similarly, an “uplink” beam may be either a transmit beam or areceive beam, depending on the entity forming it. For example, if a basestation is forming the uplink beam, it is an uplink receive beam, and ifa UE is forming the uplink beam, it is an uplink transmit beam.

The electromagnetic spectrum is often subdivided, based onfrequency/wavelength, into various classes, bands, channels, etc. In 5GNR two initial operating bands have been identified as frequency rangedesignations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). Itshould be understood that although a portion of FR1 is greater than 6GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band invarious documents and articles. A similar nomenclature issue sometimesoccurs with regard to FR2, which is often referred to (interchangeably)as a “millimeter wave” band in documents and articles, despite beingdifferent from the extremely high frequency (EHF) band (30 GHz-300 GHz)which is identified by the International Telecommunications Union (ITU)as a “millimeter wave” band.

The frequencies between FR1 and FR2 are often referred to as mid-bandfrequencies. Recent 5G NR studies have identified an operating band forthese mid-band frequencies as frequency range designation FR3 (7.125GHz-24.25 GHz). Frequency bands falling within FR3 may inherit FR1characteristics and/or FR2 characteristics, and thus may effectivelyextend features of FR1 and/or FR2 into mid-band frequencies. Inaddition, higher frequency bands are currently being explored to extend5G NR operation beyond 52.6 GHz. For example, three higher operatingbands have been identified as frequency range designations FR4a or FR4-1(52.6 GHz-71 GHz), FR4 (52.6 GHz-114.25 GHz), and FR5 (114.25 GHz-300GHz). Each of these higher frequency bands falls within the EHF band.

With the above aspects in mind, unless specifically stated otherwise, itshould be understood that the term “sub-6 GHz” or the like if usedherein may broadly represent frequencies that may be less than 6 GHz,may be within FR1, or may include mid-band frequencies. Further, unlessspecifically stated otherwise, it should be understood that the term“millimeter wave” or the like if used herein may broadly representfrequencies that may include mid-band frequencies, may be within FR2,FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.

In a multi-carrier system, such as 5G, one of the carrier frequencies isreferred to as the “primary carrier” or “anchor carrier” or “primaryserving cell” or “PCell,” and the remaining carrier frequencies arereferred to as “secondary carriers” or “secondary serving cells” or“SCells.” In carrier aggregation, the anchor carrier is the carrieroperating on the primary frequency (e.g., FR1) utilized by a UE 104/182and the cell in which the UE 104/182 either performs the initial radioresource control (RRC) connection establishment procedure or initiatesthe RRC connection re-establishment procedure. The primary carriercarries all common and UE-specific control channels, and may be acarrier in a licensed frequency (however, this is not always the case).A secondary carrier is a carrier operating on a second frequency (e.g.,FR2) that may be configured once the RRC connection is establishedbetween the UE 104 and the anchor carrier and that may be used toprovide additional radio resources. In some cases, the secondary carriermay be a carrier in an unlicensed frequency. The secondary carrier maycontain only necessary signaling information and signals, for example,those that are UE-specific may not be present in the secondary carrier,since both primary uplink and downlink carriers are typicallyUE-specific. This means that different UEs 104/182 in a cell may havedifferent downlink primary carriers. The same is true for the uplinkprimary carriers. The network is able to change the primary carrier ofany UE 104/182 at any time. This is done, for example, to balance theload on different carriers. Because a “serving cell” (whether a PCell oran SCell) corresponds to a carrier frequency/component carrier overwhich some base station is communicating, the term “cell,” “servingcell,” “component carrier,” “carrier frequency,” and the like can beused interchangeably.

For example, still referring to FIG. 1 , one of the frequencies utilizedby the macro cell base stations 102 may be an anchor carrier (or“PCell”) and other frequencies utilized by the macro cell base stations102 and/or the mmW base station 180 may be secondary carriers(“SCells”). The simultaneous transmission and/or reception of multiplecarriers enables the UE 104/182 to significantly increase its datatransmission and/or reception rates. For example, two 20 MHz aggregatedcarriers in a multi-carrier system would theoretically lead to atwo-fold increase in data rate (i.e., 40 MHz), compared to that attainedby a single 20 MHz carrier.

The wireless communications system 100 may further include a UE 164 thatmay communicate with a macro cell base station 102 over a communicationlink 120 and/or the mmW base station 180 over a mmW communication link184. For example, the macro cell base station 102 may support a PCelland one or more SCells for the UE 164 and the mmW base station 180 maysupport one or more SCells for the UE 164.

In some cases, the UE 164 and the UE 182 may be capable of sidelinkcommunication. Sidelink-capable UEs (SL-UEs) may communicate with basestations 102 over communication links 120 using the Uu interface (i.e.,the air interface between a UE and a base station). SL-UEs (e.g., UE164, UE 182) may also communicate directly with each other over awireless sidelink 160 using the PC5 interface (i.e., the air interfacebetween sidelink-capable UEs). A wireless sidelink (or just “sidelink”)is an adaptation of the core cellular (e.g., LTE, NR) standard thatallows direct communication between two or more UEs without thecommunication needing to go through a base station. Sidelinkcommunication may be unicast or multicast, and may be used fordevice-to-device (D2D) media-sharing, vehicle-to-vehicle (V2V)communication, vehicle-to-everything (V2X) communication (e.g., cellularV2X (cV2X) communication, enhanced V2X (eV2X) communication, etc.),emergency rescue applications, etc. One or more of a group of SL-UEsutilizing sidelink communications may be within the geographic coveragearea 110 of a base station 102. Other SL-UEs in such a group may beoutside the geographic coverage area 110 of a base station 102 or beotherwise unable to receive transmissions from a base station 102. Insome cases, groups of SL-UEs communicating via sidelink communicationsmay utilize a one-to-many (1:M) system in which each SL-UE transmits toevery other SL-UE in the group. In some cases, a base station 102facilitates the scheduling of resources for sidelink communications. Inother cases, sidelink communications are carried out between SL-UEswithout the involvement of a base station 102.

In an aspect, the sidelink 160 may operate over a wireless communicationmedium of interest, which may be shared with other wirelesscommunications between other vehicles and/or infrastructure accesspoints, as well as other RATs. A “medium” may be composed of one or moretime, frequency, and/or space communication resources (e.g.,encompassing one or more channels across one or more carriers)associated with wireless communication between one or moretransmitter/receiver pairs. In an aspect, the medium of interest maycorrespond to at least a portion of an unlicensed frequency band sharedamong various RATs. Although different licensed frequency bands havebeen reserved for certain communication systems (e.g., by a governmententity such as the Federal Communications Commission (FCC) in the UnitedStates), these systems, in particular those employing small cell accesspoints, have recently extended operation into unlicensed frequency bandssuch as the Unlicensed National Information Infrastructure (U-NII) bandused by wireless local area network (WLAN) technologies, most notablyIEEE 802.11x WLAN technologies generally referred to as “Wi-Fi.” Examplesystems of this type include different variants of CDMA systems, TDMAsystems, FDMA systems, orthogonal FDMA (OFDMA) systems, single-carrierFDMA (SC-FDMA) systems, and so on.

Note that although FIG. 1 only illustrates two of the UEs as SL-UEs(i.e., UEs 164 and 182), any of the illustrated UEs may be SL-UEs.Further, although only UE 182 was described as being capable ofbeamforming, any of the illustrated UEs, including UE 164, may becapable of beamforming. Where SL-UEs are capable of beamforming, theymay beamform towards each other (i.e., towards other SL-UEs), towardsother UEs (e.g., UEs 104), towards base stations (e.g., base stations102, 180, small cell 102′, access point 150), etc. Thus, in some cases,UEs 164 and 182 may utilize beamforming over sidelink 160.

In the example of FIG. 1 , any of the illustrated UEs (shown in FIG. 1as a single UE 104 for simplicity) may receive signals 124 from one ormore Earth orbiting space vehicles (SVs) 112 (e.g., satellites). In anaspect, the SVs 112 may be part of a satellite positioning system that aUE 104 can use as an independent source of location information. Asatellite positioning system typically includes a system of transmitters(e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) todetermine their location on or above the Earth based, at least in part,on positioning signals (e.g., signals 124) received from thetransmitters. Such a transmitter typically transmits a signal markedwith a repeating pseudo-random noise (PN) code of a set number of chips.While typically located in SVs 112, transmitters may sometimes belocated on ground-based control stations, base stations 102, and/orother UEs 104. A UE 104 may include one or more dedicated receiversspecifically designed to receive signals 124 for deriving geo locationinformation from the SVs 112.

In a satellite positioning system, the use of signals 124 can beaugmented by various satellite-based augmentation systems (SBAS) thatmay be associated with or otherwise enabled for use with one or moreglobal and/or regional navigation satellite systems. For example an SBASmay include an augmentation system(s) that provides integrityinformation, differential corrections, etc., such as the Wide AreaAugmentation System (WAAS), the European Geostationary NavigationOverlay Service (EGNOS), the Multi-functional Satellite AugmentationSystem (MSAS), the Global Positioning System (GPS) Aided Geo AugmentedNavigation or GPS and Geo Augmented Navigation system (GAGAN), and/orthe like. Thus, as used herein, a satellite positioning system mayinclude any combination of one or more global and/or regional navigationsatellites associated with such one or more satellite positioningsystems.

In an aspect, SVs 112 may additionally or alternatively be part of oneor more non-terrestrial networks (NTNs). In an NTN, an SV 112 isconnected to an earth station (also referred to as a ground station, NTNgateway, or gateway), which in turn is connected to an element in a 5Gnetwork, such as a modified base station 102 (without a terrestrialantenna) or a network node in a 5GC. This element would in turn provideaccess to other elements in the 5G network and ultimately to entitiesexternal to the 5G network, such as Internet web servers and other userdevices. In that way, a UE 104 may receive communication signals (e.g.,signals 124) from an SV 112 instead of, or in addition to, communicationsignals from a terrestrial base station 102.

The wireless communications system 100 may further include one or moreUEs, such as UE 190, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links (referred to as “sidelinks”). In the example ofFIG. 1 , UE 190 has a D2D P2P link 192 with one of the UEs 104 connectedto one of the base stations 102 (e.g., through which UE 190 mayindirectly obtain cellular connectivity) and a D2D P2P link 194 withWLAN STA 152 connected to the WLAN AP 150 (through which UE 190 mayindirectly obtain WLAN-based Internet connectivity). In an example, theD2D P2P links 192 and 194 may be supported with any well-known D2D RAT,such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on.

FIG. 2A illustrates an example wireless network structure 200. Forexample, a 5GC 210 (also referred to as a Next Generation Core (NGC))can be viewed functionally as control plane (C-plane) functions 214(e.g., UE registration, authentication, network access, gatewayselection, etc.) and user plane (U-plane) functions 212, (e.g., UEgateway function, access to data networks, IP routing, etc.) whichoperate cooperatively to form the core network. User plane interface(NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 tothe 5GC 210 and specifically to the user plane functions 212 and controlplane functions 214, respectively. In an additional configuration, anng-eNB 224 may also be connected to the 5GC 210 via NG-C 215 to thecontrol plane functions 214 and NG-U 213 to user plane functions 212.Further, ng-eNB 224 may directly communicate with gNB 222 via a backhaulconnection 223. In some configurations, a Next Generation RAN (NG-RAN)220 may have one or more gNBs 222, while other configurations includeone or more of both ng-eNBs 224 and gNBs 222. Either (or both) gNB 222or ng-eNB 224 may communicate with one or more UEs 204 (e.g., any of theUEs described herein).

Another optional aspect may include a location server 230, which may bein communication with the 5GC 210 to provide location assistance forUE(s) 204. The location server 230 can be implemented as a plurality ofseparate servers (e.g., physically separate servers, different softwaremodules on a single server, different software modules spread acrossmultiple physical servers, etc.), or alternately may each correspond toa single server. The location server 230 can be configured to supportone or more location services for UEs 204 that can connect to thelocation server 230 via the core network, 5GC 210, and/or via theInternet (not illustrated). Further, the location server 230 may beintegrated into a component of the core network, or alternatively may beexternal to the core network (e.g., a third party server, such as anoriginal equipment manufacturer (OEM) server or service server).

FIG. 2B illustrates another example wireless network structure 240. A5GC 260 (which may correspond to 5GC 210 in FIG. 2A) can be viewedfunctionally as control plane functions, provided by an access andmobility management function (AMF) 264, and user plane functions,provided by a user plane function (UPF) 262, which operate cooperativelyto form the core network (i.e., 5GC 260). The functions of the AMF 264include registration management, connection management, reachabilitymanagement, mobility management, lawful interception, transport forsession management (SM) messages between one or more UEs 204 (e.g., anyof the UEs described herein) and a session management function (SMF)266, transparent proxy services for routing SM messages, accessauthentication and access authorization, transport for short messageservice (SMS) messages between the UE 204 and the short message servicefunction (SMSF) (not shown), and security anchor functionality (SEAF).The AMF 264 also interacts with an authentication server function (AUSF)(not shown) and the UE 204, and receives the intermediate key that wasestablished as a result of the UE 204 authentication process. In thecase of authentication based on a UMTS (universal mobiletelecommunications system) subscriber identity module (USIM), the AMF264 retrieves the security material from the AUSF. The functions of theAMF 264 also include security context management (SCM). The SCM receivesa key from the SEAF that it uses to derive access-network specific keys.The functionality of the AMF 264 also includes location servicesmanagement for regulatory services, transport for location servicesmessages between the UE 204 and a location management function (LMF) 270(which acts as a location server 230), transport for location servicesmessages between the NG-RAN 220 and the LMF 270, evolved packet system(EPS) bearer identifier allocation for interworking with the EPS, and UE204 mobility event notification. In addition, the AMF 264 also supportsfunctionalities for non-3GPP (Third Generation Partnership Project)access networks.

Functions of the UPF 262 include acting as an anchor point forintra-/inter-RAT mobility (when applicable), acting as an externalprotocol data unit (PDU) session point of interconnect to a data network(not shown), providing packet routing and forwarding, packet inspection,user plane policy rule enforcement (e.g., gating, redirection, trafficsteering), lawful interception (user plane collection), traffic usagereporting, quality of service (QoS) handling for the user plane (e.g.,uplink/downlink rate enforcement, reflective QoS marking in thedownlink), uplink traffic verification (service data flow (SDF) to QoSflow mapping), transport level packet marking in the uplink anddownlink, downlink packet buffering and downlink data notificationtriggering, and sending and forwarding of one or more “end markers” tothe source RAN node. The UPF 262 may also support transfer of locationservices messages over a user plane between the UE 204 and a locationserver, such as an SLP 272.

The functions of the SMF 266 include session management, UE Internetprotocol (IP) address allocation and management, selection and controlof user plane functions, configuration of traffic steering at the UPF262 to route traffic to the proper destination, control of part ofpolicy enforcement and QoS, and downlink data notification. Theinterface over which the SMF 266 communicates with the AMF 264 isreferred to as the N11 interface.

Another optional aspect may include an LMF 270, which may be incommunication with the 5GC 260 to provide location assistance for UEs204. The LMF 270 can be implemented as a plurality of separate servers(e.g., physically separate servers, different software modules on asingle server, different software modules spread across multiplephysical servers, etc.), or alternately may each correspond to a singleserver. The LMF 270 can be configured to support one or more locationservices for UEs 204 that can connect to the LMF 270 via the corenetwork, 5GC 260, and/or via the Internet (not illustrated). The SLP 272may support similar functions to the LMF 270, but whereas the LMF 270may communicate with the AMF 264, NG-RAN 220, and UEs 204 over a controlplane (e.g., using interfaces and protocols intended to convey signalingmessages and not voice or data), the SLP 272 may communicate with UEs204 and external clients (e.g., third-party server 274) over a userplane (e.g., using protocols intended to carry voice and/or data likethe transmission control protocol (TCP) and/or IP).

Yet another optional aspect may include a third-party server 274, whichmay be in communication with the LMF 270, the SLP 272, the 5GC 260(e.g., via the AMF 264 and/or the UPF 262), the NG-RAN 220, and/or theUE 204 to obtain location information (e.g., a location estimate) forthe UE 204. As such, in some cases, the third-party server 274 may bereferred to as a location services (LCS) client or an external client.The third-party server 274 can be implemented as a plurality of separateservers (e.g., physically separate servers, different software moduleson a single server, different software modules spread across multiplephysical servers, etc.), or alternately may each correspond to a singleserver.

User plane interface 263 and control plane interface 265 connect the 5GC260, and specifically the UPF 262 and AMF 264, respectively, to one ormore gNBs 222 and/or ng-eNBs 224 in the NG-RAN 220. The interfacebetween gNB(s) 222 and/or ng-eNB(s) 224 and the AMF 264 is referred toas the “N2” interface, and the interface between gNB(s) 222 and/orng-eNB(s) 224 and the UPF 262 is referred to as the “N3” interface. ThegNB(s) 222 and/or ng-eNB(s) 224 of the NG-RAN 220 may communicatedirectly with each other via backhaul connections 223, referred to asthe “Xn-C” interface. One or more of gNBs 222 and/or ng-eNBs 224 maycommunicate with one or more UEs 204 over a wireless interface, referredto as the “Uu” interface.

The functionality of a gNB 222 may be divided between a gNB central unit(gNB-CU) 226, one or more gNB distributed units (gNB-DUs) 228, and oneor more gNB radio units (gNB-RUs) 229. A gNB-CU 226 is a logical nodethat includes the base station functions of transferring user data,mobility control, radio access network sharing, positioning, sessionmanagement, and the like, except for those functions allocatedexclusively to the gNB-DU(s) 228. More specifically, the gNB-CU 226generally host the radio resource control (RRC), service data adaptationprotocol (SDAP), and packet data convergence protocol (PDCP) protocolsof the gNB 222. A gNB-DU 228 is a logical node that generally hosts theradio link control (RLC) and medium access control (MAC) layer of thegNB 222. Its operation is controlled by the gNB-CU 226. One gNB-DU 228can support one or more cells, and one cell is supported by only onegNB-DU 228. The interface 232 between the gNB-CU 226 and the one or moregNB-DUs 228 is referred to as the “F1” interface. The physical (PHY)layer functionality of a gNB 222 is generally hosted by one or morestandalone gNB-RUs 229 that perform functions such as poweramplification and signal transmission/reception. The interface between agNB-DU 228 and a gNB-RU 229 is referred to as the “Fx” interface. Thus,a UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCPlayers, with a gNB-DU 228 via the RLC and MAC layers, and with a gNB-RU229 via the PHY layer.

Deployment of communication systems, such as 5G NR systems, may bearranged in multiple manners with various components or constituentparts. In a 5G NR system, or network, a network node, a network entity,a mobility element of a network, a RAN node, a core network node, anetwork element, or a network equipment, such as a base station, or oneor more units (or one or more components) performing base stationfunctionality, may be implemented in an aggregated or disaggregatedarchitecture. For example, a base station (such as a Node B (NB),evolved NB (eNB), NR base station, 5G NB, access point (AP), a transmitreceive point (TRP), or a cell, etc.) may be implemented as anaggregated base station (also known as a standalone base station or amonolithic base station) or a disaggregated base station.

An aggregated base station may be configured to utilize a radio protocolstack that is physically or logically integrated within a single RANnode. A disaggregated base station may be configured to utilize aprotocol stack that is physically or logically distributed among two ormore units (such as one or more central or centralized units (CUs), oneor more distributed units (DUs), or one or more radio units (RUs)). Insome aspects, a CU may be implemented within a RAN node, and one or moreDUs may be co-located with the CU, or alternatively, may begeographically or virtually distributed throughout one or multiple otherRAN nodes. The DUs may be implemented to communicate with one or moreRUs. Each of the CU, DU and RU also can be implemented as virtual units,i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), ora virtual radio unit (VRU).

Base station-type operation or network design may consider aggregationcharacteristics of base station functionality. For example,disaggregated base stations may be utilized in an integrated accessbackhaul (IAB) network, an open radio access network (O-RAN (such as thenetwork configuration sponsored by the O-RAN Alliance)), or avirtualized radio access network (vRAN, also known as a cloud radioaccess network (C-RAN)). Disaggregation may include distributingfunctionality across two or more units at various physical locations, aswell as distributing functionality for at least one unit virtually,which can enable flexibility in network design. The various units of thedisaggregated base station, or disaggregated RAN architecture, can beconfigured for wired or wireless communication with at least one otherunit.

FIG. 2C illustrates an example disaggregated base station architecture250, according to aspects of the disclosure. The disaggregated basestation architecture 250 may include one or more central units (CUs) 280(e.g., gNB-CU 226) that can communicate directly with a core network 267(e.g., 5GC 210, 5GC 260) via a backhaul link, or indirectly with thecore network 267 through one or more disaggregated base station units(such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 259via an E2 link, or a Non-Real Time (Non-RT) RIC 257 associated with aService Management and Orchestration (SMO) Framework 255, or both). A CU280 may communicate with one or more distributed units (DUs) 285 (e.g.,gNB-DUs 228) via respective midhaul links, such as an F1 interface. TheDUs 285 may communicate with one or more radio units (RUs) 287 (e.g.,gNB-RUs 229) via respective fronthaul links. The RUs 287 may communicatewith respective UEs 204 via one or more radio frequency (RF) accesslinks. In some implementations, the UE 204 may be simultaneously servedby multiple RUs 287.

Each of the units, i.e., the CUs 280, the DUs 285, the RUs 287, as wellas the Near-RT RICs 259, the Non-RT RICs 257 and the SMO Framework 255,may include one or more interfaces or be coupled to one or moreinterfaces configured to receive or transmit signals, data, orinformation (collectively, signals) via a wired or wireless transmissionmedium. Each of the units, or an associated processor or controllerproviding instructions to the communication interfaces of the units, canbe configured to communicate with one or more of the other units via thetransmission medium. For example, the units can include a wiredinterface configured to receive or transmit signals over a wiredtransmission medium to one or more of the other units. Additionally, theunits can include a wireless interface, which may include a receiver, atransmitter or transceiver (such as a radio frequency (RF) transceiver),configured to receive or transmit signals, or both, over a wirelesstransmission medium to one or more of the other units.

In some aspects, the CU 280 may host one or more higher layer controlfunctions. Such control functions can include radio resource control(RRC), packet data convergence protocol (PDCP), service data adaptationprotocol (SDAP), or the like. Each control function can be implementedwith an interface configured to communicate signals with other controlfunctions hosted by the CU 280. The CU 280 may be configured to handleuser plane functionality (i.e., Central Unit—User Plane (CU-UP)),control plane functionality (i.e., Central Unit—Control Plane (CU-CP)),or a combination thereof. In some implementations, the CU 280 can belogically split into one or more CU-UP units and one or more CU-CPunits. The CU-UP unit can communicate bidirectionally with the CU-CPunit via an interface, such as the E1 interface when implemented in anO-RAN configuration. The CU 280 can be implemented to communicate withthe DU 285, as necessary, for network control and signaling.

The DU 285 may correspond to a logical unit that includes one or morebase station functions to control the operation of one or more RUs 287.In some aspects, the DU 285 may host one or more of a radio link control(RLC) layer, a medium access control (MAC) layer, and one or more highphysical (PHY) layers (such as modules for forward error correction(FEC) encoding and decoding, scrambling, modulation and demodulation, orthe like) depending, at least in part, on a functional split, such asthose defined by the 3rd Generation Partnership Project (3GPP). In someaspects, the DU 285 may further host one or more low PHY layers. Eachlayer (or module) can be implemented with an interface configured tocommunicate signals with other layers (and modules) hosted by the DU285, or with the control functions hosted by the CU 280.

Lower-layer functionality can be implemented by one or more RUs 287. Insome deployments, an RU 287, controlled by a DU 285, may correspond to alogical node that hosts RF processing functions, or low-PHY layerfunctions (such as performing fast Fourier transform (FFT), inverse FFT(iFFT), digital beamforming, physical random access channel (PRACH)extraction and filtering, or the like), or both, based at least in parton the functional split, such as a lower layer functional split. In suchan architecture, the RU(s) 287 can be implemented to handle over the air(OTA) communication with one or more UEs 204. In some implementations,real-time and non-real-time aspects of control and user planecommunication with the RU(s) 287 can be controlled by the correspondingDU 285. In some scenarios, this configuration can enable the DU(s) 285and the CU 280 to be implemented in a cloud-based RAN architecture, suchas a vRAN architecture.

The SMO Framework 255 may be configured to support RAN deployment andprovisioning of non-virtualized and virtualized network elements. Fornon-virtualized network elements, the SMO Framework 255 may beconfigured to support the deployment of dedicated physical resources forRAN coverage requirements which may be managed via an operations andmaintenance interface (such as an O1 interface). For virtualized networkelements, the SMO Framework 255 may be configured to interact with acloud computing platform (such as an open cloud (O-Cloud) 269) toperform network element life cycle management (such as to instantiatevirtualized network elements) via a cloud computing platform interface(such as an O2 interface). Such virtualized network elements caninclude, but are not limited to, CUs 280, DUs 285, RUs 287 and Near-RTRICs 259. In some implementations, the SMO Framework 255 can communicatewith a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 261, viaan O1 interface. Additionally, in some implementations, the SMOFramework 255 can communicate directly with one or more RUs 287 via anO1 interface. The SMO Framework 255 also may include a Non-RT RIC 257configured to support functionality of the SMO Framework 255.

The Non-RT RIC 257 may be configured to include a logical function thatenables non-real-time control and optimization of RAN elements andresources, Artificial Intelligence/Machine Learning (AI/ML) workflowsincluding model training and updates, or policy-based guidance ofapplications/features in the Near-RT RIC 259. The Non-RT RIC 257 may becoupled to or communicate with (such as via an A1 interface) the Near-RTRIC 259. The Near-RT RIC 259 may be configured to include a logicalfunction that enables near-real-time control and optimization of RANelements and resources via data collection and actions over an interface(such as via an E2 interface) connecting one or more CUs 280, one ormore DUs 285, or both, as well as an O-eNB, with the Near-RT RIC 259.

In some implementations, to generate AI/ML models to be deployed in theNear-RT RIC 259, the Non-RT RIC 257 may receive parameters or externalenrichment information from external servers. Such information may beutilized by the Near-RT RIC 259 and may be received at the SMO Framework255 or the Non-RT RIC 257 from non-network data sources or from networkfunctions. In some examples, the Non-RT RIC 257 or the Near-RT RIC 259may be configured to tune RAN behavior or performance. For example, theNon-RT RIC 257 may monitor long-term trends and patterns for performanceand employ AI/ML models to perform corrective actions through the SMOFramework 255 (such as reconfiguration via 01) or via creation of RANmanagement policies (such as A1 policies).

FIGS. 3A, 3B, and 3C illustrate several example components (representedby corresponding blocks) that may be incorporated into a UE 302 (whichmay correspond to any of the UEs described herein), a base station 304(which may correspond to any of the base stations described herein), anda network entity 306 (which may correspond to or embody any of thenetwork functions described herein, including the location server 230and the LMF 270, or alternatively may be independent from the NG-RAN 220and/or 5GC 210/260 infrastructure depicted in FIGS. 2A and 2B, such as aprivate network) to support the operations described herein. It will beappreciated that these components may be implemented in different typesof apparatuses in different implementations (e.g., in an ASIC, in asystem-on-chip (SoC), etc.). The illustrated components may also beincorporated into other apparatuses in a communication system. Forexample, other apparatuses in a system may include components similar tothose described to provide similar functionality. Also, a givenapparatus may contain one or more of the components. For example, anapparatus may include multiple transceiver components that enable theapparatus to operate on multiple carriers and/or communicate viadifferent technologies.

The UE 302 and the base station 304 each include one or more wirelesswide area network (WWAN) transceivers 310 and 350, respectively,providing means for communicating (e.g., means for transmitting, meansfor receiving, means for measuring, means for tuning, means forrefraining from transmitting, etc.) via one or more wirelesscommunication networks (not shown), such as an NR network, an LTEnetwork, a GSM network, and/or the like. The WWAN transceivers 310 and350 may each be connected to one or more antennas 316 and 356,respectively, for communicating with other network nodes, such as otherUEs, access points, base stations (e.g., eNBs, gNBs), etc., via at leastone designated RAT (e.g., NR, LTE, GSM, etc.) over a wirelesscommunication medium of interest (e.g., some set of time/frequencyresources in a particular frequency spectrum). The WWAN transceivers 310and 350 may be variously configured for transmitting and encodingsignals 318 and 358 (e.g., messages, indications, information, and soon), respectively, and, conversely, for receiving and decoding signals318 and 358 (e.g., messages, indications, information, pilots, and soon), respectively, in accordance with the designated RAT. Specifically,the WWAN transceivers 310 and 350 include one or more transmitters 314and 354, respectively, for transmitting and encoding signals 318 and358, respectively, and one or more receivers 312 and 352, respectively,for receiving and decoding signals 318 and 358, respectively.

The UE 302 and the base station 304 each also include, at least in somecases, one or more short-range wireless transceivers 320 and 360,respectively. The short-range wireless transceivers 320 and 360 may beconnected to one or more antennas 326 and 366, respectively, and providemeans for communicating (e.g., means for transmitting, means forreceiving, means for measuring, means for tuning, means for refrainingfrom transmitting, etc.) with other network nodes, such as other UEs,access points, base stations, etc., via at least one designated RAT(e.g., WiFi, LTE-D, Bluetooth®, Zigbee®, Z-Wave®, PC5, dedicatedshort-range communications (DSRC), wireless access for vehicularenvironments (WAVE), near-field communication (NFC), ultra-wideband(UWB), etc.) over a wireless communication medium of interest. Theshort-range wireless transceivers 320 and 360 may be variouslyconfigured for transmitting and encoding signals 328 and 368 (e.g.,messages, indications, information, and so on), respectively, and,conversely, for receiving and decoding signals 328 and 368 (e.g.,messages, indications, information, pilots, and so on), respectively, inaccordance with the designated RAT. Specifically, the short-rangewireless transceivers 320 and 360 include one or more transmitters 324and 364, respectively, for transmitting and encoding signals 328 and368, respectively, and one or more receivers 322 and 362, respectively,for receiving and decoding signals 328 and 368, respectively. Asspecific examples, the short-range wireless transceivers 320 and 360 maybe WiFi transceivers, Bluetooth® transceivers, Zigbee® and/or Z-Wave®transceivers, NFC transceivers, UWB transceivers, or vehicle-to-vehicle(V2V) and/or vehicle-to-everything (V2X) transceivers.

The UE 302 and the base station 304 also include, at least in somecases, satellite signal receivers 330 and 370. The satellite signalreceivers 330 and 370 may be connected to one or more antennas 336 and376, respectively, and may provide means for receiving and/or measuringsatellite positioning/communication signals 338 and 378, respectively.Where the satellite signal receivers 330 and 370 are satellitepositioning system receivers, the satellite positioning/communicationsignals 338 and 378 may be global positioning system (GPS) signals,global navigation satellite system (GLONASS) signals, Galileo signals,Beidou signals, Indian Regional Navigation Satellite System (NAVIC),Quasi-Zenith Satellite System (QZSS), etc. Where the satellite signalreceivers 330 and 370 are non-terrestrial network (NTN) receivers, thesatellite positioning/communication signals 338 and 378 may becommunication signals (e.g., carrying control and/or user data)originating from a 5G network. The satellite signal receivers 330 and370 may comprise any suitable hardware and/or software for receiving andprocessing satellite positioning/communication signals 338 and 378,respectively. The satellite signal receivers 330 and 370 may requestinformation and operations as appropriate from the other systems, and,at least in some cases, perform calculations to determine locations ofthe UE 302 and the base station 304, respectively, using measurementsobtained by any suitable satellite positioning system algorithm.

The base station 304 and the network entity 306 each include one or morenetwork transceivers 380 and 390, respectively, providing means forcommunicating (e.g., means for transmitting, means for receiving, etc.)with other network entities (e.g., other base stations 304, othernetwork entities 306). For example, the base station 304 may employ theone or more network transceivers 380 to communicate with other basestations 304 or network entities 306 over one or more wired or wirelessbackhaul links. As another example, the network entity 306 may employthe one or more network transceivers 390 to communicate with one or morebase station 304 over one or more wired or wireless backhaul links, orwith other network entities 306 over one or more wired or wireless corenetwork interfaces.

A transceiver may be configured to communicate over a wired or wirelesslink. A transceiver (whether a wired transceiver or a wirelesstransceiver) includes transmitter circuitry (e.g., transmitters 314,324, 354, 364) and receiver circuitry (e.g., receivers 312, 322, 352,362). A transceiver may be an integrated device (e.g., embodyingtransmitter circuitry and receiver circuitry in a single device) in someimplementations, may comprise separate transmitter circuitry andseparate receiver circuitry in some implementations, or may be embodiedin other ways in other implementations. The transmitter circuitry andreceiver circuitry of a wired transceiver (e.g., network transceivers380 and 390 in some implementations) may be coupled to one or more wirednetwork interface ports. Wireless transmitter circuitry (e.g.,transmitters 314, 324, 354, 364) may include or be coupled to aplurality of antennas (e.g., antennas 316, 326, 356, 366), such as anantenna array, that permits the respective apparatus (e.g., UE 302, basestation 304) to perform transmit “beamforming,” as described herein.Similarly, wireless receiver circuitry (e.g., receivers 312, 322, 352,362) may include or be coupled to a plurality of antennas (e.g.,antennas 316, 326, 356, 366), such as an antenna array, that permits therespective apparatus (e.g., UE 302, base station 304) to perform receivebeamforming, as described herein. In an aspect, the transmittercircuitry and receiver circuitry may share the same plurality ofantennas (e.g., antennas 316, 326, 356, 366), such that the respectiveapparatus can only receive or transmit at a given time, not both at thesame time. A wireless transceiver (e.g., WWAN transceivers 310 and 350,short-range wireless transceivers 320 and 360) may also include anetwork listen module (NLM) or the like for performing variousmeasurements.

As used herein, the various wireless transceivers (e.g., transceivers310, 320, 350, and 360, and network transceivers 380 and 390 in someimplementations) and wired transceivers (e.g., network transceivers 380and 390 in some implementations) may generally be characterized as “atransceiver,” “at least one transceiver,” or “one or more transceivers.”As such, whether a particular transceiver is a wired or wirelesstransceiver may be inferred from the type of communication performed.For example, backhaul communication between network devices or serverswill generally relate to signaling via a wired transceiver, whereaswireless communication between a UE (e.g., UE 302) and a base station(e.g., base station 304) will generally relate to signaling via awireless transceiver.

The UE 302, the base station 304, and the network entity 306 alsoinclude other components that may be used in conjunction with theoperations as disclosed herein. The UE 302, the base station 304, andthe network entity 306 include one or more processors 332, 384, and 394,respectively, for providing functionality relating to, for example,wireless communication, and for providing other processingfunctionality. The processors 332, 384, and 394 may therefore providemeans for processing, such as means for determining, means forcalculating, means for receiving, means for transmitting, means forindicating, etc. In an aspect, the processors 332, 384, and 394 mayinclude, for example, one or more general purpose processors, multi-coreprocessors, central processing units (CPUs), ASICs, digital signalprocessors (DSPs), field programmable gate arrays (FPGAs), otherprogrammable logic devices or processing circuitry, or variouscombinations thereof.

The UE 302, the base station 304, and the network entity 306 includememory circuitry implementing memories 340, 386, and 396 (e.g., eachincluding a memory device), respectively, for maintaining information(e.g., information indicative of reserved resources, thresholds,parameters, and so on). The memories 340, 386, and 396 may thereforeprovide means for storing, means for retrieving, means for maintaining,etc. In some cases, the UE 302, the base station 304, and the networkentity 306 may include positioning component 342, 388, and 398,respectively. The positioning component 342, 388, and 398 may behardware circuits that are part of or coupled to the processors 332,384, and 394, respectively, that, when executed, cause the UE 302, thebase station 304, and the network entity 306 to perform thefunctionality described herein. In other aspects, the positioningcomponent 342, 388, and 398 may be external to the processors 332, 384,and 394 (e.g., part of a modem processing system, integrated withanother processing system, etc.). Alternatively, the positioningcomponent 342, 388, and 398 may be memory modules stored in the memories340, 386, and 396, respectively, that, when executed by the processors332, 384, and 394 (or a modem processing system, another processingsystem, etc.), cause the UE 302, the base station 304, and the networkentity 306 to perform the functionality described herein. FIG. 3Aillustrates possible locations of the positioning component 342, whichmay be, for example, part of the one or more WWAN transceivers 310, thememory 340, the one or more processors 332, or any combination thereof,or may be a standalone component. FIG. 3B illustrates possible locationsof the positioning component 388, which may be, for example, part of theone or more WWAN transceivers 350, the memory 386, the one or moreprocessors 384, or any combination thereof, or may be a standalonecomponent. FIG. 3C illustrates possible locations of the positioningcomponent 398, which may be, for example, part of the one or morenetwork transceivers 390, the memory 396, the one or more processors394, or any combination thereof, or may be a standalone component.

The UE 302 may include one or more sensors 344 coupled to the one ormore processors 332 to provide means for sensing or detecting movementand/or orientation information that is independent of motion dataderived from signals received by the one or more WWAN transceivers 310,the one or more short-range wireless transceivers 320, and/or thesatellite signal receiver 330. By way of example, the sensor(s) 344 mayinclude an accelerometer (e.g., a micro-electrical mechanical systems(MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), analtimeter (e.g., a barometric pressure altimeter), and/or any other typeof movement detection sensor. Moreover, the sensor(s) 344 may include aplurality of different types of devices and combine their outputs inorder to provide motion information. For example, the sensor(s) 344 mayuse a combination of a multi-axis accelerometer and orientation sensorsto provide the ability to compute positions in two-dimensional (2D)and/or three-dimensional (3D) coordinate systems.

In addition, the UE 302 includes a user interface 346 providing meansfor providing indications (e.g., audible and/or visual indications) to auser and/or for receiving user input (e.g., upon user actuation of asensing device such a keypad, a touch screen, a microphone, and so on).Although not shown, the base station 304 and the network entity 306 mayalso include user interfaces.

Referring to the one or more processors 384 in more detail, in thedownlink, IP packets from the network entity 306 may be provided to theprocessor 384. The one or more processors 384 may implementfunctionality for an RRC layer, a packet data convergence protocol(PDCP) layer, a radio link control (RLC) layer, and a medium accesscontrol (MAC) layer. The one or more processors 384 may provide RRClayer functionality associated with broadcasting of system information(e.g., master information block (MIB), system information blocks(SIBs)), RRC connection control (e.g., RRC connection paging, RRCconnection establishment, RRC connection modification, and RRCconnection release), inter-RAT mobility, and measurement configurationfor UE measurement reporting; PDCP layer functionality associated withheader compression/decompression, security (ciphering, deciphering,integrity protection, integrity verification), and handover supportfunctions; RLC layer functionality associated with the transfer of upperlayer PDUs, error correction through automatic repeat request (ARQ),concatenation, segmentation, and reassembly of RLC service data units(SDUs), re-segmentation of RLC data PDUs, and reordering of RLC dataPDUs; and MAC layer functionality associated with mapping betweenlogical channels and transport channels, scheduling informationreporting, error correction, priority handling, and logical channelprioritization.

The transmitter 354 and the receiver 352 may implement Layer-1 (L1)functionality associated with various signal processing functions.Layer-1, which includes a physical (PHY) layer, may include errordetection on the transport channels, forward error correction (FEC)coding/decoding of the transport channels, interleaving, rate matching,mapping onto physical channels, modulation/demodulation of physicalchannels, and MIMO antenna processing. The transmitter 354 handlesmapping to signal constellations based on various modulation schemes(e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an orthogonalfrequency division multiplexing (OFDM) subcarrier, multiplexed with areference signal (e.g., pilot) in the time and/or frequency domain, andthen combined together using an inverse fast Fourier transform (IFFT) toproduce a physical channel carrying a time domain OFDM symbol stream.The OFDM symbol stream is spatially precoded to produce multiple spatialstreams. Channel estimates from a channel estimator may be used todetermine the coding and modulation scheme, as well as for spatialprocessing. The channel estimate may be derived from a reference signaland/or channel condition feedback transmitted by the UE 302. Eachspatial stream may then be provided to one or more different antennas356. The transmitter 354 may modulate an RF carrier with a respectivespatial stream for transmission.

At the UE 302, the receiver 312 receives a signal through its respectiveantenna(s) 316. The receiver 312 recovers information modulated onto anRF carrier and provides the information to the one or more processors332. The transmitter 314 and the receiver 312 implement Layer-1functionality associated with various signal processing functions. Thereceiver 312 may perform spatial processing on the information torecover any spatial streams destined for the UE 302. If multiple spatialstreams are destined for the UE 302, they may be combined by thereceiver 312 into a single OFDM symbol stream. The receiver 312 thenconverts the OFDM symbol stream from the time-domain to the frequencydomain using a fast Fourier transform (FFT). The frequency domain signalcomprises a separate OFDM symbol stream for each subcarrier of the OFDMsignal. The symbols on each subcarrier, and the reference signal, arerecovered and demodulated by determining the most likely signalconstellation points transmitted by the base station 304. These softdecisions may be based on channel estimates computed by a channelestimator. The soft decisions are then decoded and de-interleaved torecover the data and control signals that were originally transmitted bythe base station 304 on the physical channel. The data and controlsignals are then provided to the one or more processors 332, whichimplements Layer-3 (L3) and Layer-2 (L2) functionality.

In the uplink, the one or more processors 332 provides demultiplexingbetween transport and logical channels, packet reassembly, deciphering,header decompression, and control signal processing to recover IPpackets from the core network. The one or more processors 332 are alsoresponsible for error detection.

Similar to the functionality described in connection with the downlinktransmission by the base station 304, the one or more processors 332provides RRC layer functionality associated with system information(e.g., MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto transport blocks(TBs), demultiplexing of MAC SDUs from TBs, scheduling informationreporting, error correction through hybrid automatic repeat request(HARQ), priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator from a referencesignal or feedback transmitted by the base station 304 may be used bythe transmitter 314 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the transmitter 314 may be provided to different antenna(s)316. The transmitter 314 may modulate an RF carrier with a respectivespatial stream for transmission.

The uplink transmission is processed at the base station 304 in a mannersimilar to that described in connection with the receiver function atthe UE 302. The receiver 352 receives a signal through its respectiveantenna(s) 356. The receiver 352 recovers information modulated onto anRF carrier and provides the information to the one or more processors384.

In the uplink, the one or more processors 384 provides demultiplexingbetween transport and logical channels, packet reassembly, deciphering,header decompression, control signal processing to recover IP packetsfrom the UE 302. IP packets from the one or more processors 384 may beprovided to the core network. The one or more processors 384 are alsoresponsible for error detection.

For convenience, the UE 302, the base station 304, and/or the networkentity 306 are shown in FIGS. 3A, 3B, and 3C as including variouscomponents that may be configured according to the various examplesdescribed herein. It will be appreciated, however, that the illustratedcomponents may have different functionality in different designs. Inparticular, various components in FIGS. 3A to 3C are optional inalternative configurations and the various aspects includeconfigurations that may vary due to design choice, costs, use of thedevice, or other considerations. For example, in case of FIG. 3A, aparticular implementation of UE 302 may omit the WWAN transceiver(s) 310(e.g., a wearable device or tablet computer or PC or laptop may haveWi-Fi and/or Bluetooth capability without cellular capability), or mayomit the short-range wireless transceiver(s) 320 (e.g., cellular-only,etc.), or may omit the satellite signal receiver 330, or may omit thesensor(s) 344, and so on. In another example, in case of FIG. 3B, aparticular implementation of the base station 304 may omit the WWANtransceiver(s) 350 (e.g., a Wi-Fi “hotspot” access point withoutcellular capability), or may omit the short-range wirelesstransceiver(s) 360 (e.g., cellular-only, etc.), or may omit thesatellite signal receiver 370, and so on. For brevity, illustration ofthe various alternative configurations is not provided herein, but wouldbe readily understandable to one skilled in the art.

The various components of the UE 302, the base station 304, and thenetwork entity 306 may be communicatively coupled to each other overdata buses 334, 382, and 392, respectively. In an aspect, the data buses334, 382, and 392 may form, or be part of, a communication interface ofthe UE 302, the base station 304, and the network entity 306,respectively. For example, where different logical entities are embodiedin the same device (e.g., gNB and location server functionalityincorporated into the same base station 304), the data buses 334, 382,and 392 may provide communication between them.

The components of FIGS. 3A, 3B, and 3C may be implemented in variousways. In some implementations, the components of FIGS. 3A, 3B, and 3Cmay be implemented in one or more circuits such as, for example, one ormore processors and/or one or more ASICs (which may include one or moreprocessors). Here, each circuit may use and/or incorporate at least onememory component for storing information or executable code used by thecircuit to provide this functionality. For example, some or all of thefunctionality represented by blocks 310 to 346 may be implemented byprocessor and memory component(s) of the UE 302 (e.g., by execution ofappropriate code and/or by appropriate configuration of processorcomponents). Similarly, some or all of the functionality represented byblocks 350 to 388 may be implemented by processor and memorycomponent(s) of the base station 304 (e.g., by execution of appropriatecode and/or by appropriate configuration of processor components). Also,some or all of the functionality represented by blocks 390 to 398 may beimplemented by processor and memory component(s) of the network entity306 (e.g., by execution of appropriate code and/or by appropriateconfiguration of processor components). For simplicity, variousoperations, acts, and/or functions are described herein as beingperformed “by a UE,” “by a base station,” “by a network entity,” etc.However, as will be appreciated, such operations, acts, and/or functionsmay actually be performed by specific components or combinations ofcomponents of the UE 302, base station 304, network entity 306, etc.,such as the processors 332, 384, 394, the transceivers 310, 320, 350,and 360, the memories 340, 386, and 396, the positioning component 342,388, and 398, etc.

In some designs, the network entity 306 may be implemented as a corenetwork component. In other designs, the network entity 306 may bedistinct from a network operator or operation of the cellular networkinfrastructure (e.g., NG RAN 220 and/or 5GC 210/260). For example, thenetwork entity 306 may be a component of a private network that may beconfigured to communicate with the UE 302 via the base station 304 orindependently from the base station 304 (e.g., over a non-cellularcommunication link, such as WiFi).

NR supports a number of cellular network-based positioning technologies,including downlink-based, uplink-based, and downlink-and-uplink-basedpositioning methods. Downlink-based positioning methods include observedtime difference of arrival (OTDOA) in LTE, downlink time difference ofarrival (DL-TDOA) in NR, and downlink angle-of-departure (DL-AoD) in NR.FIG. 4 illustrates examples of various positioning methods, according toaspects of the disclosure. In an OTDOA or DL-TDOA positioning procedure,illustrated by scenario 410, a UE measures the differences between thetimes of arrival (ToAs) of reference signals (e.g., positioningreference signals (PRS)) received from pairs of base stations, referredto as reference signal time difference (RSTD) or time difference ofarrival (TDOA) measurements, and reports them to a positioning entity.More specifically, the UE receives the identifiers (IDs) of a referencebase station (e.g., a serving base station) and multiple non-referencebase stations in assistance data. The UE then measures the RSTD betweenthe reference base station and each of the non-reference base stations.Based on the known locations of the involved base stations and the RSTDmeasurements, the positioning entity (e.g., the UE for UE-basedpositioning or a location server for UE-assisted positioning) canestimate the UE's location.

For DL-AoD positioning, illustrated by scenario 420, the positioningentity uses a measurement report from the UE of received signal strengthmeasurements of multiple downlink transmit beams to determine theangle(s) between the UE and the transmitting base station(s). Thepositioning entity can then estimate the location of the UE based on thedetermined angle(s) and the known location(s) of the transmitting basestation(s).

Uplink-based positioning methods include uplink time difference ofarrival (UL-TDOA) and uplink angle-of-arrival (UL-AoA). UL-TDOA issimilar to DL-TDOA, but is based on uplink reference signals (e.g.,sounding reference signals (SRS)) transmitted by the UE to multiple basestations. Specifically, a UE transmits one or more uplink referencesignals that are measured by a reference base station and a plurality ofnon-reference base stations. Each base station then reports thereception time (referred to as the relative time of arrival (RTOA)) ofthe reference signal(s) to a positioning entity (e.g., a locationserver) that knows the locations and relative timing of the involvedbase stations. Based on the reception-to-reception (Rx-Rx) timedifference between the reported RTOA of the reference base station andthe reported RTOA of each non-reference base station, the knownlocations of the base stations, and their known timing offsets, thepositioning entity can estimate the location of the UE using TDOA.

For UL-AoA positioning, one or more base stations measure the receivedsignal strength of one or more uplink reference signals (e.g., SRS)received from a UE on one or more uplink receive beams. The positioningentity uses the signal strength measurements and the angle(s) of thereceive beam(s) to determine the angle(s) between the UE and the basestation(s). Based on the determined angle(s) and the known location(s)of the base station(s), the positioning entity can then estimate thelocation of the UE.

Downlink-and-uplink-based positioning methods include enhanced cell-ID(E-CID) positioning and multi-round-trip-time (RTT) positioning (alsoreferred to as “multi-cell RTT” and “multi-RTT”). In an RTT procedure, afirst entity (e.g., a base station or a UE) transmits a firstRTT-related signal (e.g., a PRS or SRS) to a second entity (e.g., a UEor base station), which transmits a second RTT-related signal (e.g., anSRS or PRS) back to the first entity. Each entity measures the timedifference between the time of arrival (ToA) of the received RTT-relatedsignal and the transmission time of the transmitted RTT-related signal.This time difference is referred to as a reception-to-transmission(Rx-Tx) time difference. The Rx-Tx time difference measurement may bemade, or may be adjusted, to include only a time difference betweennearest slot boundaries for the received and transmitted signals. Bothentities may then send their Rx-Tx time difference measurement to alocation server (e.g., an LMF 270), which calculates the round trippropagation time (i.e., RTT) between the two entities from the two Rx-Txtime difference measurements (e.g., as the sum of the two Rx-Tx timedifference measurements). Alternatively, one entity may send its Rx-Txtime difference measurement to the other entity, which then calculatesthe RTT. The distance between the two entities can be determined fromthe RTT and the known signal speed (e.g., the speed of light). Formulti-RTT positioning, illustrated by scenario 430, a first entity(e.g., a UE or base station) performs an RTT positioning procedure withmultiple second entities (e.g., multiple base stations or UEs) to enablethe location of the first entity to be determined (e.g., usingmultilateration) based on distances to, and the known locations of, thesecond entities. RTT and multi-RTT methods can be combined with otherpositioning techniques, such as UL-AoA and DL-AoD, to improve locationaccuracy, as illustrated by scenario 440.

The E-CID positioning method is based on radio resource management (RRM)measurements. In E-CID, the UE reports the serving cell ID, the timingadvance (TA), and the identifiers, estimated timing, and signal strengthof detected neighbor base stations. The location of the UE is thenestimated based on this information and the known locations of the basestation(s).

To assist positioning operations, a location server (e.g., locationserver 230, LMF 270, SLP 272) may provide assistance data to the UE. Forexample, the assistance data may include identifiers of the basestations (or the cells/TRPs of the base stations) from which to measurereference signals, the reference signal configuration parameters (e.g.,the number of consecutive slots including PRS, periodicity of theconsecutive slots including PRS, muting sequence, frequency hoppingsequence, reference signal identifier, reference signal bandwidth,etc.), and/or other parameters applicable to the particular positioningmethod. Alternatively, the assistance data may originate directly fromthe base stations themselves (e.g., in periodically broadcasted overheadmessages, etc.). In some cases, the UE may be able to detect neighbornetwork nodes itself without the use of assistance data.

In the case of an OTDOA or DL-TDOA positioning procedure, the assistancedata may further include an expected RSTD value and an associateduncertainty, or search window, around the expected RSTD. In some cases,the value range of the expected RSTD may be +/−500 microseconds (μs). Insome cases, when any of the resources used for the positioningmeasurement are in FR1, the value range for the uncertainty of theexpected RSTD may be +/−32 μs. In other cases, when all of the resourcesused for the positioning measurement(s) are in FR2, the value range forthe uncertainty of the expected RSTD may be +/−8 μs.

A location estimate may be referred to by other names, such as aposition estimate, location, position, position fix, fix, or the like. Alocation estimate may be geodetic and comprise coordinates (e.g.,latitude, longitude, and possibly altitude) or may be civic and comprisea street address, postal address, or some other verbal description of alocation. A location estimate may further be defined relative to someother known location or defined in absolute terms (e.g., using latitude,longitude, and possibly altitude). A location estimate may include anexpected error or uncertainty (e.g., by including an area or volumewithin which the location is expected to be included with some specifiedor default level of confidence).

Various frame structures may be used to support downlink and uplinktransmissions between network nodes (e.g., base stations and UEs). FIG.5 is a diagram 500 illustrating an example frame structure, according toaspects of the disclosure. The frame structure may be a downlink oruplink frame structure. Other wireless communications technologies mayhave different frame structures and/or different channels.

LTE, and in some cases NR, utilizes orthogonal frequency-divisionmultiplexing (OFDM) on the downlink and single-carrier frequencydivision multiplexing (SC-FDM) on the uplink. Unlike LTE, however, NRhas an option to use OFDM on the uplink as well. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kilohertz (kHz) andthe minimum resource allocation (resource block) may be 12 subcarriers(or 180 kHz). Consequently, the nominal fast Fourier transform (FFT)size may be equal to 128, 256, 512, 1024, or 2048 for system bandwidthof 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The systembandwidth may also be partitioned into subbands. For example, a subbandmay cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4,8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz,respectively.

LTE supports a single numerology (subcarrier spacing (SCS), symbollength, etc.). In contrast, NR may support multiple numerologies (μ),for example, subcarrier spacings of 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz(μ=2), 120 kHz (μ=3), and 240 kHz (μ=4) or greater may be available. Ineach subcarrier spacing, there are 14 symbols per slot. For 15 kHz SCS(μ=0), there is one slot per subframe, 10 slots per frame, the slotduration is 1 millisecond (ms), the symbol duration is 66.7 microseconds(μs), and the maximum nominal system bandwidth (in MHz) with a 4K FFTsize is 50. For 30 kHz SCS (μ=1), there are two slots per subframe, 20slots per frame, the slot duration is 0.5 ms, the symbol duration is33.3 μs, and the maximum nominal system bandwidth (in MHz) with a 4K FFTsize is 100. For 60 kHz SCS (μ=2), there are four slots per subframe, 40slots per frame, the slot duration is 0.25 ms, the symbol duration is16.7 μs, and the maximum nominal system bandwidth (in MHz) with a 4K FFTsize is 200. For 120 kHz SCS (μ=3), there are eight slots per subframe,80 slots per frame, the slot duration is 0.125 ms, the symbol durationis 8.33 μs, and the maximum nominal system bandwidth (in MHz) with a 4KFFT size is 400. For 240 kHz SCS (μ=4), there are 16 slots per subframe,160 slots per frame, the slot duration is 0.0625 ms, the symbol durationis 4.17 μs, and the maximum nominal system bandwidth (in MHz) with a 4KFFT size is 800.

In the example of FIG. 5 , a numerology of 15 kHz is used. Thus, in thetime domain, a 10 ms frame is divided into 10 equally sized subframes of1 ms each, and each subframe includes one time slot. In FIG. 5 , time isrepresented horizontally (on the X axis) with time increasing from leftto right, while frequency is represented vertically (on the Y axis) withfrequency increasing (or decreasing) from bottom to top.

A resource grid may be used to represent time slots, each time slotincluding one or more time-concurrent resource blocks (RBs) (alsoreferred to as physical RBs (PRBs)) in the frequency domain. Theresource grid is further divided into multiple resource elements (REs).An RE may correspond to one symbol length in the time domain and onesubcarrier in the frequency domain. In the numerology of FIG. 5 , for anormal cyclic prefix, an RB may contain 12 consecutive subcarriers inthe frequency domain and seven consecutive symbols in the time domain,for a total of 84 REs. For an extended cyclic prefix, an RB may contain12 consecutive subcarriers in the frequency domain and six consecutivesymbols in the time domain, for a total of 72 REs. The number of bitscarried by each RE depends on the modulation scheme.

Some of the REs may carry reference (pilot) signals (RS). The referencesignals may include positioning reference signals (PRS), trackingreference signals (TRS), phase tracking reference signals (PTRS),cell-specific reference signals (CRS), channel state informationreference signals (CSI-RS), demodulation reference signals (DMRS),primary synchronization signals (PSS), secondary synchronization signals(SSS), synchronization signal blocks (SSBs), sounding reference signals(SRS), etc., depending on whether the illustrated frame structure isused for uplink or downlink communication. FIG. 5 illustrates examplelocations of REs carrying a reference signal (labeled “R”).

A collection of resource elements (REs) that are used for transmissionof PRS is referred to as a “PRS resource.” The collection of resourceelements can span multiple PRBs in the frequency domain and ‘N’ (such as1 or more) consecutive symbol(s) within a slot in the time domain. In agiven OFDM symbol in the time domain, a PRS resource occupiesconsecutive PRBs in the frequency domain.

The transmission of a PRS resource within a given PRB has a particularcomb size (also referred to as the “comb density”). A comb size ‘N’represents the subcarrier spacing (or frequency/tone spacing) withineach symbol of a PRS resource configuration. Specifically, for a combsize ‘N,’ PRS are transmitted in every Nth subcarrier of a symbol of aPRB. For example, for comb-4, for each symbol of the PRS resourceconfiguration, REs corresponding to every fourth subcarrier (such assubcarriers 0, 4, 8) are used to transmit PRS of the PRS resource.Currently, comb sizes of comb-2, comb-4, comb-6, and comb-12 aresupported for DL-PRS. FIG. 5 illustrates an example PRS resourceconfiguration for comb-4 (which spans four symbols). That is, thelocations of the shaded REs (labeled “R”) indicate a comb-4 PRS resourceconfiguration.

Currently, a DL-PRS resource may span 2, 4, 6, or 12 consecutive symbolswithin a slot with a fully frequency-domain staggered pattern. A DL-PRSresource can be configured in any higher layer configured downlink orflexible (FL) symbol of a slot. There may be a constant energy perresource element (EPRE) for all REs of a given DL-PRS resource. Thefollowing are the frequency offsets from symbol to symbol for comb sizes2, 4, 6, and 12 over 2, 4, 6, and 12 symbols. 2-symbol comb-2: {0, 1};4-symbol comb-2: {0, 1, 0, 1}; 6-symbol comb-2: {0, 1, 0, 1, 0, 1};12-symbol comb-2: {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}; 4-symbol comb-4:{0, 2, 1, 3} (as in the example of FIG. 5 ); 12-symbol comb-4: {0, 2, 1,3, 0, 2, 1, 3, 0, 2, 1, 3}; 6-symbol comb-6: {0, 3, 1, 4, 2, 5};12-symbol comb-6: {0, 3, 1, 4, 2, 5, 0, 3, 1, 4, 2, 5}; and 12-symbolcomb-12: {0, 6, 3, 9, 1, 7, 4, 10, 2, 8, 5, 11}.

A “PRS resource set” is a set of PRS resources used for the transmissionof PRS signals, where each PRS resource has a PRS resource ID. Inaddition, the PRS resources in a PRS resource set are associated withthe same TRP. A PRS resource set is identified by a PRS resource set IDand is associated with a particular TRP (identified by a TRP ID). Inaddition, the PRS resources in a PRS resource set have the sameperiodicity, a common muting pattern configuration, and the samerepetition factor (such as “PRS-ResourceRepetitionFactor”) across slots.The periodicity is the time from the first set repetition of the firstPRS resource of a first PRS instance to the same first repetition of thesame first PRS resource of the next PRS instance. The periodicity mayhave a length selected from 2{circumflex over ( )}*{4, 5, 8, 10, 16, 20,32, 40, 64, 80, 160, 320, 640, 1280, 2560, 5120, 10240} slots, with p=0,1, 2, 3. The repetition factor may have a length selected from {1, 2, 4,6, 8, 16, 32} slots.

A PRS resource ID in a PRS resource set is associated with a single beam(or beam ID) transmitted from a single TRP (where a TRP may transmit oneor more beams). That is, each PRS resource of a PRS resource set may betransmitted on a different beam, and as such, a “PRS resource,” orsimply “resource,” also can be referred to as a “beam.” Note that thisdoes not have any implications on whether the TRPs and the beams onwhich PRS are transmitted are known to the UE.

A “PRS instance” or “PRS occasion” is one instance of a periodicallyrepeated time window (such as a group of one or more consecutive slots)where PRS are expected to be transmitted. A PRS occasion also may bereferred to as a “PRS positioning occasion,” a “PRS positioninginstance, a “positioning occasion,” “a positioning instance,” a“positioning repetition,” or simply an “occasion,” an “instance,” or a“repetition.”

A “positioning frequency layer” (also referred to simply as a “frequencylayer”) is a collection of one or more PRS resource sets across one ormore TRPs that have the same values for certain parameters.Specifically, the collection of PRS resource sets has the samesubcarrier spacing and cyclic prefix (CP) type (meaning all numerologiessupported for the physical downlink shared channel (PDSCH) are alsosupported for PRS), the same Point A, the same value of the downlink PRSbandwidth, the same start PRB (and center frequency), and the samecomb-size. The Point A parameter takes the value of the parameter“ARFCN-ValueNR” (where “ARFCN” stands for “absolute radio-frequencychannel number”) and is an identifier/code that specifies a pair ofphysical radio channel used for transmission and reception. The downlinkPRS bandwidth may have a granularity of four PRBs, with a minimum of 24PRBs and a maximum of 272 PRBs. Currently, up to four frequency layershave been defined, and up to two PRS resource sets may be configured perTRP per frequency layer.

The concept of a frequency layer is somewhat like the concept ofcomponent carriers and bandwidth parts (BWPs), but different in thatcomponent carriers and BWPs are used by one base station (or a macrocell base station and a small cell base station) to transmit datachannels, while frequency layers are used by several (usually three ormore) base stations to transmit PRS. A UE may indicate the number offrequency layers it can support when it sends the network itspositioning capabilities, such as during an LTE positioning protocol(LPP) session. For example, a UE may indicate whether it can support oneor four positioning frequency layers.

Note that the terms “positioning reference signal” and “PRS” generallyrefer to specific reference signals that are used for positioning in NRand LTE systems. However, as used herein, the terms “positioningreference signal” and “PRS” may also refer to any type of referencesignal that can be used for positioning, such as but not limited to, PRSas defined in LTE and NR, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB,SRS, UL-PRS, etc. In addition, the terms “positioning reference signal”and “PRS” may refer to downlink, uplink, or sidelink positioningreference signals, unless otherwise indicated by the context. If neededto further distinguish the type of PRS, a downlink positioning referencesignal may be referred to as a “DL-PRS,” an uplink positioning referencesignal (e.g., an SRS-for-positioning, PTRS) may be referred to as an“UL-PRS,” and a sidelink positioning reference signal may be referred toas an “SL-PRS.” In addition, for signals that may be transmitted in thedownlink, uplink, and/or sidelink (e.g., DMRS), the signals may beprepended with “DL,” “UL,” or “SL” to distinguish the direction. Forexample, “UL-DMRS” is different from “DL-DMRS.”

FIG. 6 is a graph 600 representing the channel estimate of a multipathchannel between a receiver device (e.g., any of the UEs or base stationsdescribed herein) and a transmitter device (e.g., any other of the UEsor base stations described herein), according to aspects of thedisclosure. The channel estimate represents the intensity of a radiofrequency (RF) signal (e.g., a PRS) received through a multipath channelas a function of time delay, and may be referred to as the channelenergy response (CER), channel impulse response (CIR), or power delayprofile (PDP) of the channel. Thus, the horizontal axis is in units oftime (e.g., milliseconds) and the vertical axis is in units of signalstrength (e.g., decibels). Note that a multipath channel is a channelbetween a transmitter and a receiver over which an RF signal followsmultiple paths, or multipaths, due to transmission of the RF signal onmultiple beams and/or to the propagation characteristics of the RFsignal (e.g., reflection, refraction, etc.).

In the example of FIG. 6 , the receiver detects/measures multiple (four)clusters of channel taps. Each channel tap represents a multipath thatan RF signal followed between the transmitter and the receiver. That is,a channel tap represents the arrival of an RF signal on a multipath.Each cluster of channel taps indicates that the corresponding multipathsfollowed essentially the same path. There may be different clusters dueto the RF signal being transmitted on different transmit beams (andtherefore at different angles), or because of the propagationcharacteristics of RF signals (e.g., potentially following differentpaths due to reflections), or both.

All of the clusters of channel taps for a given RF signal represent themultipath channel (or simply channel) between the transmitter andreceiver. Under the channel illustrated in FIG. 6 , the receiverreceives a first cluster of two RF signals on channel taps at time T1, asecond cluster of five RF signals on channel taps at time T2, a thirdcluster of five RF signals on channel taps at time T3, and a fourthcluster of four RF signals on channel taps at time T4. In the example ofFIG. 6 , because the first cluster of RF signals at time T1 arrivesfirst, it is assumed to correspond to the RF signal transmitted on thetransmit beam aligned with the line-of-sight (LOS), or the shortest,path. The third cluster at time T3 is comprised of the strongest RFsignals, and may correspond to, for example, the RF signal transmittedon a transmit beam aligned with a non-line-of-sight (NLOS) path. Notethat although FIG. 6 illustrates clusters of two to five channel taps,as will be appreciated, the clusters may have more or fewer than theillustrated number of channel taps.

Machine learning (ML), or other techniques, may be used to generatemodels that may be used to facilitate various aspects associated withprocessing of data. One specific application of ML relates to generationof positioning models for processing of reference signals forpositioning (e.g., PRS), such as feature extraction, reporting ofreference signal measurements (e.g., selecting which extracted featuresto report), and so on.

ML models are generally categorized as either supervised orunsupervised. A supervised model may further be sub-categorized aseither a regression or classification model. Supervised learninginvolves learning a function that maps an input to an output based onexample input-output pairs. For example, given a training dataset withtwo variables of age (input) and height (output), a supervised learningmodel could be generated to predict the height of a person based ontheir age. In regression models, the output is continuous. One exampleof a regression model is a linear regression, which simply attempts tofind a line that best fits the data. Extensions of linear regressioninclude multiple linear regression (e.g., finding a plane of best fit)and polynomial regression (e.g., finding a curve of best fit).

Another example of an ML model is a decision tree model. In a decisiontree model, a tree structure is defined with a plurality of nodes.Decisions are used to move from a root node at the top of the decisiontree to a leaf node at the bottom of the decision tree (i.e., a nodewith no further child nodes). Generally, a higher number of nodes in thedecision tree model is correlated with higher decision accuracy.

Another example of an MIL model is a decision forest. Random forests arean ensemble learning technique that builds off of decision trees. Randomforests involve creating multiple decision trees using bootstrappeddatasets of the original data and randomly selecting a subset ofvariables at each step of the decision tree. The model then selects themode of all of the predictions of each decision tree. By relying on a“majority wins” model, the risk of error from an individual tree isreduced.

Another example of an MII, model is a neural network (NN). A neuralnetwork is essentially a network of mathematical equations. Neuralnetworks accept one or more input variables, and by going through anetwork of equations, result in one or more output variables. Putanother way, a neural network takes in a vector of inputs and returns avector of outputs.

FIG. 7 illustrates an example neural network 700, according to aspectsof the disclosure. The neural network 700 includes an input layer ‘i’that receives ‘n’ (one or more) inputs (illustrated as “Input 1,” “Input2,” and “Input n”), one or more hidden layers (illustrated as hiddenlayers ‘h1,’ ‘h2,’ and ‘h3’) for processing the inputs from the inputlayer, and an output layer ‘o’ that provides ‘m’ (one or more) outputs(labeled “Output 1” and “Output m”). The number of inputs ‘n,’ hiddenlayers ‘h,’ and outputs ‘m’ may be the same or different. In somedesigns, the hidden layers ‘h’ may include linear function(s) and/oractivation function(s) that the nodes (illustrated as circles) of eachsuccessive hidden layer process from the nodes of the previous hiddenlayer.

In classification models, the output is discrete. One example of aclassification model is logistic regression. Logistic regression issimilar to linear regression but is used to model the probability of afinite number of outcomes, typically two. In essence, a logisticequation is created in such a way that the output values can only bebetween ‘0’ and ‘1.’ Another example of a classification model is asupport vector machine. For example, for two classes of data, a supportvector machine will find a hyperplane or a boundary between the twoclasses of data that maximizes the margin between the two classes. Thereare many planes that can separate the two classes, but only one planecan maximize the margin or distance between the classes. Another exampleof a classification model is Naïve Bayes, which is based on BayesTheorem. Other examples of classification models include decision tree,random forest, and neural network, similar to the examples describedabove except that the output is discrete rather than continuous.

Unlike supervised learning, unsupervised learning is used to drawinferences and find patterns from input data without references tolabeled outcomes. Two examples of unsupervised learning models includeclustering and dimensionality reduction.

Clustering is an unsupervised technique that involves the grouping, orclustering, of data points. Clustering is frequently used for customersegmentation, fraud detection, and document classification. Commonclustering techniques include k-means clustering, hierarchicalclustering, mean shift clustering, and density-based clustering.Dimensionality reduction is the process of reducing the number of randomvariables under consideration by obtaining a set of principal variables.In simpler terms, dimensionality reduction is the process of reducingthe dimension of a feature set (in even simpler terms, reducing thenumber of features). Most dimensionality reduction techniques can becategorized as either feature elimination or feature extraction. Oneexample of dimensionality reduction is called principal componentanalysis (PCA). In the simplest sense, PCA involves project higherdimensional data (e.g., three dimensions) to a smaller space (e.g., twodimensions). This results in a lower dimension of data (e.g., twodimensions instead of three dimensions) while keeping all originalvariables in the model.

Regardless of which ML model is used, at a high-level, an ML module(e.g., implemented by a processing system, such as processors 332, 384,or 394) may be configured to iteratively analyze training input data(e.g., measurements of reference signals to/from various target UEs) andto associate this training input data with an output data set (e.g., aset of possible or likely candidate locations of the various targetUEs), thereby enabling later determination of the same output data setwhen presented with similar input data (e.g., from other target UEs atthe same or similar location).

NR supports RF fingerprint (RFFP)-based positioning, a type ofpositioning and localization technique that utilizes RFFPs captured bymobile devices to determine the locations of the mobile devices. An RFFPmay be a histogram of a received signal strength indicator (RSSI), aCER, a CIR, a PDP, or a channel frequency response (CFR). An RFFP mayrepresent a single channel received from a transmitter (e.g., a PRS),all channels received from a particular transmitter, or all channelsdetectable at the receiver. The RFFP(s) measured by a mobile device(e.g., a UE) and the locations of the transmitter(s) associated with themeasured RFFP(s) (i.e., the transmitters transmitting the RF signalsmeasured by the mobile device to determine the RFFP(s)) can be used todetermine (e.g., triangulate) the location of the mobile device.

Model-based positioning techniques have been shown to provide superiorpositioning performance when compared to classical positioning schemes.In ML-RFFP-based positioning, an ML model (e.g., neural network 700)takes as input the RFFPs of downlink reference signals (e.g., PRS) andoutputs the positioning measurement (e.g., ToA, RSTD) or mobile devicelocation corresponding to the inputted RFFPs. The ML model (e.g., neuralnetwork 700) is trained using the “ground truth” (i.e., known)positioning measurements or mobile device locations as the reference(i.e., expected) output of a training set of RFFPs.

For example, an ML model may be trained to determine the RSTDmeasurement of a pair of TRPs from RFFPs of PRS transmitted by the TRPs.The reference output for training such a model would be the correct(i.e., ground truth) RSTD measurement for the location of the mobiledevice at the time the mobile device obtained the RFFP measurements ofthe PRS. The network (e.g., location server) can determine the RSTD thatwould be expected for the pair of TRPs based on the known location ofthe mobile device and the known locations of the involved (measured)TRPs. The known location of the mobile device may be determined frommultiple reported RSTD measurements and/or any other measurementsreported by the mobile device (e.g., GPS measurements).

FIG. 8 is a diagram 800 illustrating the use of an ML model forRFFP-based positioning, according to aspects of the disclosure. In theexample of FIG. 8 , during an “offline” stage, RFFPs (e.g.,CERs/CIRs/CFRs) captured by a mobile device are stored in a database.The database may be located at the mobile device or a network entity(e.g., a location server), and each RFFP may include measurements of RFsignals (or channels or links) transmitted by one or more transmitters,illustrated in FIG. 8 as base stations 1 to N (i.e., “BS 1” to “BS N”).For UE-based downlink RFFP (DL-RFFP) positioning, the network (e.g., thelocation server) configures the base stations to transmit downlinkreference signals (e.g., PRS) to the mobile device, and the RFFPs arethe CER(s)/CIR(s)/CFR(s) of the configured downlink reference signalsdetected by the mobile device. Although the disclosure describesapplication of ML positioning models to RFFP measurements, it will berecognized, based on the teachings of the present disclosure, that othertypes of positioning models may be used in addition to, or asalternatives to ML positioning models.

Each measured RFFP is associated with the known location of the mobiledevice at the time the mobile device measured the RFFP, illustrated inFIG. 8 as positions 1 to L (i.e., “Pos 1” to “Pos L”). The mobiledevice's location may be known via another positioning technique, suchas discussed above with reference to FIG. 4 . Note that although FIG. 8illustrates RFFP information for a single mobile device, as will beappreciated, RFFP information for multiple mobile devices can becollected and stored in the database.

Based on the information captured during the offline stage, an ML model(e.g., neural network 700) is trained to predict the location of amobile device based on RFFPs measured by the mobile devices. Morespecifically, a training set of RFFP measurements is used as input tothe ML model and the known locations of the mobile devices whencapturing the RFFPs are used as labels. After training, during an“online” stage, the trained ML model can be used to predict (infer) thelocation of a mobile device (illustrated as “Pos M”) based on theRFFP(s) currently measured by the mobile device. For UE-based RFFPpositioning, the network (e.g., the location server) provides thetrained ML model to the mobile device. For UE-assisted positioning, themobile device may provide the RFFP measurements to the network forprocessing.

Note that although FIG. 8 illustrates using an RFFP-based ML model toestimate the location of a UE, the outputs (or extracted features) ofthe ML model may instead be positioning measurements based on the inputRFFPs, such as RSTD measurements, ToA measurements, DL-AoD measurements,etc.

FIG. 9 is a diagram 900 illustrating an example inference cycle forUE-based DL-RFFP positioning, according to aspects of the disclosure. Asshown in FIG. 9 , the location server (e.g., LMF 270) configures DL-PRSresources to be transmitted by one or more TRPs during a positioningsession with a UE. The TRP(s) then transmit the configured DL-PRS to theUE, which measures the RFFPs of the DL-PRS.

In the example of FIG. 9 , the location server previously trained an MLmodel for RFFP positioning (labeled “RFFP ML”), as discussed above withreference to FIGS. 7 and 8 . The location server provides the ML modelto the UE to perform inferences (e.g., determining a positioningmeasurement based on the measured RFFPs) during the positioning session.As such, after measuring the RFFPs of the DL-PRS, the UE inputs themeasured RFFPs to the received ML model to obtain the associatedpositioning measurement(s) (e.g., ToA, RSTD).

FIG. 10 illustrates an example call flow 1000 for UE-based DL-RFFPpositioning, according to aspects of the disclosure. At stage 1, the UE204 and LMF 270 perform an LPP positioning capability transfer procedureduring which the UE 204 provides its positioning capabilities to the LMF270. At stage 2, the LMF 270 provides assistance information to the UE's204 serving ng-eNB/gNB 222/224 and any neighboring ng-eNBs/gNBs 222/224,such as the PRS resource configuration of the DL-PRS to be transmittedto the UE 204. At stage 3, the UE 204 and LMF 270 perform an LPPassistance data exchange. During the exchange, the LMF 270 providesassistance data to the UE 204 for the positioning session, such as theconfiguration of the DL-PRS transmitted by the involved ng-eNBs/gNBs222/224 and the ML model to use to report positioning measurements ofthe DL-PRS.

At stage 4, the LMF 270 optionally provides assistance information tothe involved ng-eNBs/gNBs 222/224 via New Radio positioning protocoltype A (NRPPa) messages. At stage 5, the serving ng-eNB/gNB 222/224optionally broadcasts the assistance information received from the LMF270 as assistance data in one or more positioning SIBs (posSIBs). Atstage 6, the LMF 270 and the UE 204 perform an LPP request/providelocation information procedure, during which the UE 204 providespositioning measurements taken of the DL-PRS transmitted by theng-eNBs/gNBs 222/224. The positioning measurements may be derived byapplying the ML model received in the assistance data to the RFFPs ofthe measured DL-PRS. The various stages illustrated in FIG. 10 will bediscussed in greater detail below.

RFFP positioning models can be trained on different environments (e.g.,through crowdsourcing, federated learning.) Nevertheless, challengesexist given the sheer variety of environments and propagation conditions(e.g., a single indoor factory environment where machines and objects inthe environment often change depending on the current productionsystem).

Certain aspects of the disclosure are implemented with a recognitionthat successful deployment and usage of positioning models for RFFPpositioning may benefit from 1) timely monitoring (e.g., generallycontinuous monitoring) of the validity of the positioning model, and 2)selection of a fallback positioning technique that does not use thepositioning model in response to determining that the positioning modelis invalid or has otherwise failed. To this end, methods of wirelesscommunication performed by a UE are disclosed that facilitate monitoringthe validity of positioning models used by the UE for RFFP positioning.In certain aspects, the UE may autonomously revert to a fallbackpositioning technique if the UE determines that the positioning modelhas failed.

The UE may determine that the positioning model has failed when thepositioning model does not provide position estimates that meet positionthreshold requirements. For example, the UE may determine that thepositioning model has failed based on the number of positioning modelerror instances that have occurred.

In an aspect, positioning model error “instances” may be accumulated andused to determine that the positioning model has failed (e.g., thepositioning model is unsuitable for use in the current positioningenvironment). Certain aspects of the disclosure consider different typesof positioning model error “instances,” any of which may be used aloneor in combination to determine that the positioning model is unsuitablefor continued use in the current positioning environment. One type ofpositioning model error instance in accordance with aspects of thedisclosure is referenced herein as an “uncertainty error instance.”Another type of positioning model error instance in accordance withaspects of the disclosure is referenced herein as a “mismatch errorinstance.” If the UE detects multiple (i.e., consecutive or accumulated)positioning model error instances, the positioning model is likely notsuitable for the current positioning environment, and anotherpositioning technique (e.g., fallback positioning technique) may beused. In certain aspects, the UE may maintain a count of the positioningmodel error instances using a counter or other counting mechanism.

Uncertainty error instances may be determined to have occurred based ona comparison of position uncertainties associated with positionestimates obtained using the positioning model (e.g., by applying thepositioning model to RFFP measurements) with positioning uncertaintyerror criteria. In this regard, the UE may associate positionuncertainty values with the position estimates obtained using thepositioning model. The position uncertainty values may be determined invarious manners. In an aspect, the positioning model may provide suchposition uncertainty values at the positioning model output along withcorresponding position estimates. Additionally, or in the alternative,the UE may determine the position uncertainty values for the positionestimates in a different manner. Regardless of how the positionuncertainty values are obtained, the UE may determine that anuncertainty error instance has occurred based on a comparison of theposition uncertainty value corresponding to a position estimate with aposition uncertainty error threshold indicated in, for example, apositioning model uncertainty error threshold indicated in positioninguncertainty error criteria. In an aspect, if a position uncertaintyvalue associated with a position estimate made during a positioningoccasion exceeds the position uncertainty threshold indicated in thepositioning uncertainty error criteria, the UE may determine that anuncertainty error instance has occurred and increase the number ofpositioning model error instances. In an aspect, the parameters of thepositioning uncertainty error criteria may be 1) indicated in one ormore LPP messages, 2) pre-configured at the UE (e.g., duringmanufacturing, prior to UE deployment, during deployment of the UEs in apositioning environment, etc.), or 3) any combination thereof.

Model mismatch error instances may be determined to have occurred basedon a comparison of position estimates obtained using the positioningmodel (e.g., by applying the positioning model to RFFP measurements) toposition estimates obtained using a positioning technique that does notuse the positioning model. For example, the UE may compare a positionestimate obtained during a positioning occasion using the positioningmodel with a second position estimate obtained during the positioningoccasion using another positioning technique that does not employ thepositioning model (e.g., a cellular-based positioning technique, aGNSS-based positioning technique, an RFFP positioning technique using adifferent positioning model, an NR positioning technique, or acombination thereof). The UE may determine a position difference betweenthe first and second position estimates. A mismatch error instance maybe determined to have occurred based on a comparison of the positiondifference with a position mismatch threshold indicated in positionmismatch error criteria. In an aspect, if the position differenceexceeds the position mismatch threshold indicated in the positionmismatch error criteria, the UE may determine that a mismatch errorinstance has occurred and increase the number of positioning model errorinstances. In an aspect, the parameters of the position mismatch errorcriteria may be 1) indicated in one or more LPP messages, 2)pre-configured at the UE, or 3) any combination thereof.

The position difference, as well as the corresponding position mismatchthreshold, can be specified in various manners. Such positiondifferences and/or thresholds may be specified as 1) a horizontal error,2) a vertical error, 3) a three-dimensional error, or 4) any combinationthereof. The position uncertainty values, as well as the correspondingpositioning uncertainty error criteria, may be specified in a similarmanner.

In certain aspects, the UE may determine that the positioning model hasfailed based on a comparison of the accumulated number of model errorinstances associated with positioning model failure criteria. Variouspositioning model failure criteria may be used. For example, the UE maycompare the total number of accumulated model error instances that occurusing the positioning model with a total number of allowable model errorinstances indicated by configured positioning model failure criteria. Inthis scenario, the UE may determine that the positioning model hasfailed when the accumulated number of model error instances exceeds thetotal number of allowable model error instances. Additionally, or in thealternative, the UE may compare the accumulated number of model errorinstances that occur over a specified time duration with a maximumnumber of allowable model error instances that may occur over the timeduration indicated by the configured positioning model failure criteria.In this scenario, the UE may determine that the positioning model hasfailed when the number of model error instances that occur over aspecified time duration exceeds the maximum number of model errorinstances that are allowable over the time duration.

The UE may respond to the failure of the positioning model in variousmanners. For example, in response to determining that the number ofmodel error instances satisfies the model failure criteria, the UE maydeactivate the positioning model. In certain aspects, the positioningmodel that has failed is not used during positioning occasions takingplace after the UE has detected the positioning model failure.Additionally, or in the alternative, the UE may activate a fallbackpositioning technique that does not use the positioning model forpositioning occasions taking place after the UE has detected thepositioning model failure. In certain aspects, the fallback technique isused for positioning occasions occurring after the UE has determinedthat the positioning model has failed.

The duration during which the fallback positioning technique is usedinstead of the positioning technique associated with the failedpositioning model may be varied. In certain aspects, the fallbacktechnique is used instead of the positioning technique associated withthe failed positioning model for all positioning occasions subsequent tothe detected positioning model failure or until remedial action has beenundertaken to restore the validity of the failed positioning model. Incertain aspects, the UE may reactivate the positioning model based on 1)expiration of a time threshold since deactivating the positioning model,2) expiration of a time threshold since activating the fallbackpositioning technique, 3) using the fallback positioning technique for athreshold number of positioning occasions, 4) receiving a request toreactivate the positioning model, or 5) any combination thereof.

The UE may be configured with the positioning model failure criteria invarious manners. In an aspect, the UE may receive a transmissionindicating one or more parameters of the positioning model failurecriteria from a network device (e.g., another UEs, a location server, anLMF, a positioning model server, etc.). The transmission indicating theone or more parameters of the model failure criteria may be received viaa first set of one or more LPP messages. Additionally, or in thealternative, the UE may be pre-configured with the one or moreparameters of the positioning model failure criteria. In certainaspects, the pre-configuration may take place prior to the execution ofthe RFFP positioning operations that use the positioning model (e.g.,during manufacturing, prior to UE deployment, during deployment of theUE in a positioning environment, etc.). It will be recognized, based onthe teachings of the present disclosure, that other manners ofconfiguring the UE with the model failure criteria may be employed.

Various positioning techniques may be used for the fallback positioningtechnique. In certain aspects, the fallback positioning technique maybe 1) a further RFFP technique using a different positioning model, 2) aGNSS positioning technique, 3) an NR positioning technique, or 4) anycombination thereof.

The UE may likewise be configured with the fallback positioningtechnique in various manners. In certain aspects, the UE may receive oneor more transmissions indicating 1) the type of positioning technique tobe used as the fallback positioning technique, 2) one or more parametersof the fallback positioning technique, or 3) any combination thereof.Additionally, or in the alternative, the UE may be pre-configuredwith 1) the type of positioning technique to be used for the fallbackpositioning technique, 2) one or more parameters of the fallbackpositioning technique, or 3) a combination thereof. In certain aspects,the pre-configuration may take place prior to the execution of the RFFPpositioning operations that use the positioning model (e.g., duringmanufacturing, prior to UE deployment, during deployment of the UEs in apositioning environment, etc.). Still further, a mix of any of theforegoing manners of configuring the fallback positioning technique maybe used. It will be recognized, based on the teachings of the presentdisclosure, that other manners of configuring the UE with the fallbackpositioning technique may be employed.

In accordance with certain aspects of the disclosure, the UE maytransmit a model failure report indicating that the positioning modelhas failed. The content and timing of the transmission of the modelfailure report may be configured by the network (e.g., location server).In various aspects, the model failure report may be transmitted inresponse to 1) determining that the positioning model has failed, 2)receiving a model failure report request (e.g., from a location server,a positioning model server, etc.), or 3) a combination thereof.

The model failure report may include various information that may beuseful in assessing the failure of the positioning model. For example,the model failure report may indicate 1) a first model identifierassociated with the first positioning model, 2) a second modelidentifier associated with a second positioning model applied to theRFFP measurements to obtain the second position estimate, 3) anidentification of one or more positioning techniques used to obtain thesecond position estimate, 4) one or more timestamps associated with oneor more positioning model error instances of the positioning model errorinstances, 5) a time span associated with determining the one or morepositioning model error instances, 6) one or more position uncertaintyerror values associated with the one or more positioning model errorinstances, 7) channel condition parameters (e.g., channel delay spread,Doppler spread, etc., if available) associated with the one or morepositioning model error instances, or 8) any combination thereof. Itwill be recognized, based on the teachings of the present disclosure,that other information may be indicated in the mismatch report, theforegoing list constituting examples of such information.

In accordance with various aspects of the disclosure, the model failurereport may be transmitted to one or more network entities. In an aspect,the network entities may be responsible for maintaining, training,and/or distributing the positioning models to a plurality of UEs in thenetwork. The network entity may be a location server (e.g., LMF).Additionally, or in the alternative, the network entity may be a modelmanagement server dedicated to managing the positioning models used bythe UEs. In either instance, the network entity may execute functionsincluding 1) distributing new positioning models to the UEs, 2)re-training the positioning model based on information in the mismatchreport, or 3) any combination thereof. Additionally, or in thealternative, such functionality may be included in the location server.

FIG. 11 through FIG. 13 depict various manners of detecting apositioning model failure, according to aspects of the disclosure. FIG.11 is a timing diagram 1100 showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances, according to aspects of the disclosure. In FIG. 11 , the UEmay employ a counter (e.g., labeled “posModelErrorInstanceCount”) thatis used to maintain a count of the total number of positioning modelerror instances that have occurred. Upon detecting a positioning modelerror instance, the UE increments the counter (e.g., increases the valueof posModelErrorInstanceCount by 1). In this example, the UE hasdetected positioning model error instances at 1102, 1104, and 1106. Whenthe value of posModelErrorInstanceCount is incremented, the value ofposModelErrorInstanceCount is compared to a maximum number of modelerror instances (labeled “posModelErrorInstanceMaxCount”) indicated bythe positioning model failure criteria. In certain aspects, the value ofposModelErrorInstanceMaxCount is selected to correspond to a valueindicating that the maximum number of allowable positioning failureinstances has been exceeded. At model error instances 1102 and 1104, thevalue of posModelErrorInstanceCount is less thanposModelErrorInstanceMaxCount, indicating that the positioning model hasnot yet failed. However, at positioning model error instance 1106, thevalue of posModelErrorInstanceCount is equal to the value ofposModelErrorInstanceMaxCount, thereby indicating that the number ofallowable positioning model instances has been exceeded. As a result,the UE determines that the positioning model has failed at positioningmodel error instance 1106.

FIG. 12 is a timing diagram 1200 showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances occurring over a specified time duration, according to aspectsof the disclosure. In addition to using the counterposModelErrorInstanceCount and posModelErrorInstanceMaxCount, theexample shown in FIG. 12 also specifies a time duration 1202 over whichthe posModelErrorInstanceCount is maintained. Although positioning modelerror instances are detected at 1210 and 1212, the value ofposModelErrorInstanceCount does not reach the value ofposModelErrorInstanceMaxCount within the time duration 1202.Consequently, the UE does not detect a positioning model failure.Rather, the UE resets the value of posModelErrorInstanceCount andrestarts tracking the number of positioning model error instances atpositioning model error instance 1214 for subsequent positioningoccasions based on the positioning model error instance criteria. Notethat the positioning model error instance criteria for the subsequentpositioning occasions may be the same or different from the positioningmodel error instance criteria shown in FIG. 12 .

The time duration 1202 may be defined in various manners. In the exampleshown in FIG. 12 , the time duration 1202 is defined by a start time1204 (labeled “PosModelFailureDetectionTimerStart”), a window timerduration value 1206 (labeled “PosModelFailureDetectionTimerDuration”),and an end time 1208 (labeled “PosModelFailureDetectionTimerExpiry”). Incertain aspects, the UE may start a timer atPosModelFailureDetectionTimer 1204 at a determined time or upon theoccurrence of a specified event (e.g., the occurrence of an initialpositioning model error instance). The timer may have a specified limit(e.g., duration count) defined by PosModelFailureDetectionTimerDuration1206. A determination is made that the timer has expired atPosModelFailureDetectionTimerExpiry 1208. It will be recognized, in viewof the teachings of the disclosure, that other manners of specifying thetime duration 1202 may be used.

FIG. 13 is a timing diagram 1300 showing an example of positioning modelfailure detection based on a total number of positioning model errorinstances occurring over a specified time duration, according to aspectsof the disclosure. At model error instances 1302 and 1304, the value ofposModelErrorInstanceCount is less than posModelErrorInstanceMaxCount,thereby indicating that the positioning model has not yet failed.However, at positioning model error instance 1306, the value ofposModelErrorInstanceCount is equal to the value ofposModelErrorInstanceMaxCount, thereby indicating that the number ofallowable positioning model instances has been exceeded before theexpiration of the time duration indicated atPosModelFailureDetectionTimerExpiry 1208. As a result, the UE determinesthat the positioning model has failed at positioning model errorinstance 1306.

FIG. 14 illustrates an example method 1400 of wireless communicationperformed by a UE, according to aspects of the disclosure. At operation1402, the UE determines that a positioning model error instance hasoccurred during a positioning occasion based on 1) a positionuncertainty associated with a first position estimate satisfyingpositioning uncertainty error criteria, wherein the first positionestimate is obtained during the positioning occasion by applying a firstpositioning model to radio frequency fingerprint (RFFP) measurements, 2)a positioning mismatch between the first position estimate of the UE anda second estimate of the UE satisfying position mismatch error criteria,wherein the second position estimate of the UE is obtained during thepositioning occasion by performing a positioning technique that does notuse the first positioning model, or 3) any combination thereof. In anaspect, operation 1402 may be performed by the one or more WWANtransceivers 310, the one or more short-range wireless transceivers 320,the one or more processors 332, memory 340, and/or positioning component342, any or all of which may be considered means for performing thisoperation.

At operation 1404, the UE determines that the first positioning modelhas failed based on a number of positioning model error instancessatisfying positioning model failure criteria. In an aspect, operation1404 may be performed by the one or more WWAN transceivers 310, the oneor more short-range wireless transceivers 320, the one or moreprocessors 332, memory 340, and/or positioning component 342, any or allof which may be considered means for performing this operation.

As will be appreciated, a technical advantage of the method 1400 is thatthe method enables the UE to detect a failure of a positioning modelused in RFFP positioning operations. Once the failure of the positioningmodel has been detected, the UE may execute various remedial measuressuch as, for example, switching to a fallback technique for subsequentpositioning occasions, reporting the positioning model failure to thenetwork, etc.

In the detailed description above it can be seen that different featuresare grouped together in examples. This manner of disclosure should notbe understood as an intention that the example clauses have morefeatures than are explicitly mentioned in each clause. Rather, thevarious aspects of the disclosure may include fewer than all features ofan individual example clause disclosed. Therefore, the following clausesshould hereby be deemed to be incorporated in the description, whereineach clause by itself can stand as a separate example. Although eachdependent clause can refer in the clauses to a specific combination withone of the other clauses, the aspect(s) of that dependent clause are notlimited to the specific combination. It will be appreciated that otherexample clauses can also include a combination of the dependent clauseaspect(s) with the subject matter of any other dependent clause orindependent clause or a combination of any feature with other dependentand independent clauses. The various aspects disclosed herein expresslyinclude these combinations, unless it is explicitly expressed or can bereadily inferred that a specific combination is not intended (e.g.,contradictory aspects, such as defining an element as both an electricalinsulator and an electrical conductor). Furthermore, it is also intendedthat aspects of a clause can be included in any other independentclause, even if the clause is not directly dependent on the independentclause.

Implementation examples are described in the following numbered clauses:

-   -   Clause 1. A method of wireless communication performed by a user        equipment (UE), comprising: determining that a positioning model        error instance has occurred during a positioning occasion based        on 1) a position uncertainty associated with a first position        estimate satisfying positioning uncertainty error criteria,        wherein the first position estimate is obtained during the        positioning occasion by applying a first positioning model to        radio frequency fingerprint (RFFP) measurements, 2) a        positioning mismatch between the first position estimate of the        UE and a second position estimate of the UE satisfying position        mismatch error criteria, wherein the second position estimate of        the UE is obtained during the positioning occasion by performing        a positioning technique that does not use the first positioning        model, or 3) any combination thereof, and determining that the        first positioning model has failed based on a number of        positioning model error instances satisfying positioning model        failure criteria.    -   Clause 2. The method of clause 1, further comprising: in        response to determining that the number of positioning model        error instances satisfies the positioning model failure        criteria, deactivating the first positioning model, and        activating a fallback positioning technique that does not use        the first positioning model in further positioning occasions.    -   Clause 3. The method of clause 2, further comprising: receiving        an indication of a type of positioning technique to be used as        the fallback positioning technique; receiving one or more        parameters of the fallback positioning technique; configuring        the UE with the type of positioning technique used for the        fallback positioning technique based on a pre-configuration of        the type of positioning technique to be used for the fallback        positioning technique at the UE; configuring the UE with the one        or more parameters of the fallback positioning technique based        on a pre-configuration of the one or more parameters of the        fallback positioning technique at the UE; or any combination        thereof.    -   Clause 4. The method of clause 3, wherein: the type of        positioning technique used for the fallback positioning        technique is received via a first set of LPP messages; the one        or more parameters of the fallback positioning technique are        received via a second set of LPP messages; or any combination        thereof.    -   Clause 5. The method of any of clauses 2 to 4, wherein the        fallback positioning technique comprises: a further RFFP        technique using a second positioning model; a Global Navigation        Satellite System (GNSS) positioning technique; a New Radio (NR)        positioning technique; or any combination thereof.    -   Clause 6. The method of any of clauses 2 to 5, further        comprising: reactivating the first positioning model based on        expiration of a time threshold since deactivating the first        positioning model, expiration of a time threshold since        activating the fallback positioning technique, using the        fallback positioning technique for a threshold number of        positioning occasions, receiving a request to reactivate the        first positioning model, or any combination thereof.    -   Clause 7. The method of any of clauses 1 to 6, wherein the        positioning model failure criteria comprises: a total number of        positioning model error instances; a number of positioning model        error instances occurring over a time duration; or any        combination thereof.    -   Clause 8. The method of any of clauses 1 to 7, wherein the        positioning uncertainty error criteria comprises: the position        uncertainty associated with the first position estimate        exceeding a position uncertainty threshold.    -   Clause 9. The method of any of clauses 1 to 8, wherein the        position mismatch error criteria comprises: a position        difference between the first position estimate and the second        position estimate exceeding a position difference threshold.    -   Clause 10. The method of any of clauses 1 to 9, further        comprising: receiving one or more parameters indicating the        positioning model failure criteria; configuring the one or more        parameters of the positioning model failure criteria based on a        pre-configuration of the one or more parameters of the        positioning model failure criteria at the UE; or a combination        thereof.    -   Clause 11. The method of clause 10, wherein: the one or more        parameters indicating the positioning model failure criteria are        received via a set of Long-Term Evolution Positioning Protocol        (LPP) messages.    -   Clause 12. The method of any of clauses 1 to 11, further        comprising: transmitting a model failure report indicating that        the first positioning model has failed.    -   Clause 13. The method of clause 12, wherein: the model failure        report is transmitted in response to determining that the number        of positioning model error instances satisfy the positioning        model failure criteria; receiving a model failure report        request; or any combination thereof.    -   Clause 14. The method of clause 13, wherein the model failure        report indicates: a first model identifier associated with the        first positioning model; a second model identifier associated        with a second positioning model applied to the RFFP measurements        to obtain the second position estimate; an identification of one        or more positioning techniques used to obtain the second        position estimate; one or more timestamps associated with one or        more positioning model error instances of the positioning model        error instances; a time span associated with determining the one        or more positioning model error instances; one or more position        uncertainty error values associated with the one or more        positioning model error instances; channel condition parameters        associated with the one or more positioning model error        instances; or any combination thereof.    -   Clause 15. A user equipment (UE), comprising: a memory; at least        one transceiver; and at least one processor communicatively        coupled to the memory and the at least one transceiver, the at        least one processor configured to: determine that a positioning        model error instance has occurred during a positioning occasion        based on 1) a position uncertainty associated with a first        position estimate satisfying positioning uncertainty error        criteria, wherein the first position estimate is obtained during        the positioning occasion by applying a first positioning model        to radio frequency fingerprint (RFFP) measurements, 2) a        positioning mismatch between the first position estimate of the        UE and a second position estimate of the UE satisfying position        mismatch error criteria, wherein the second position estimate of        the UE is obtained during the positioning occasion by performing        a positioning technique that does not use the first positioning        model, or 3) any combination thereof; and determine that the        first positioning model has failed based on a number of        positioning model error instances satisfying positioning model        failure criteria.    -   Clause 16. The UE of clause 15, wherein the at least one        processor is further configured to: in response to determining        that the number of positioning model error instances satisfies        the positioning model failure criteria, deactivate the first        positioning model, and activate a fallback positioning technique        that does not use the first positioning model in further        positioning occasions.    -   Clause 17. The UE of clause 16, wherein the at least one        processor is further configured to: receive, via the at least        one transceiver, an indication of a type of positioning        technique to be used as the fallback positioning technique;        receive, via the at least one transceiver, one or more        parameters of the fallback positioning technique; configure the        UE with the type of positioning technique used for the fallback        positioning technique based on a pre-configuration of the type        of positioning technique to be used for the fallback positioning        technique at the UE; configure the UE with the one or more        parameters of the fallback positioning technique based on a        pre-configuration of the one or more parameters of the fallback        positioning technique at the UE; or any combination thereof.    -   Clause 18. The UE of clause 17, wherein: the type of positioning        technique used for the fallback positioning technique is        received via a first set of LPP messages; the one or more        parameters of the fallback positioning technique are received        via a second set of LPP messages; or any combination thereof.    -   Clause 19. The UE of any of clauses 16 to 18, wherein the        fallback positioning technique comprises: a further RFFP        technique using a second positioning model; a Global Navigation        Satellite System (GNSS) positioning technique; a New Radio (NR)        positioning technique; or any combination thereof.    -   Clause 20. The UE of any of clauses 16 to 19, wherein the at        least one processor is further configured to: reactivate the        first positioning model based on expiration of a time threshold        since deactivating the first positioning model, expiration of a        time threshold since activating the fallback positioning        technique, using the fallback positioning technique for a        threshold number of positioning occasions, receiving, via the at        least one transceiver, a request to reactivate the first        positioning model, or any combination thereof.    -   Clause 21. The UE of any of clauses 15 to 20, wherein the        positioning model failure criteria comprises: a total number of        positioning model error instances; a number of positioning model        error instances occurring over a time duration; or any        combination thereof.    -   Clause 22. The UE of any of clauses 15 to 21, wherein the        positioning uncertainty error criteria comprises: the position        uncertainty associated with the first position estimate        exceeding a position uncertainty threshold.    -   Clause 23. The UE of any of clauses 15 to 22, wherein the        position mismatch error criteria comprises: a position        difference between the first position estimate and the second        position estimate exceeding a position difference threshold.    -   Clause 24. The UE of any of clauses 15 to 23, wherein the at        least one processor is further configured to: receive, via the        at least one transceiver, one or more parameters indicating the        positioning model failure criteria; configure the one or more        parameters of the positioning model failure criteria based on a        pre-configuration of the one or more parameters of the        positioning model failure criteria at the UE; or a combination        thereof.    -   Clause 25. The UE of clause 24, wherein: the one or more        parameters indicating the positioning model failure criteria are        received via a set of Long-Term Evolution Positioning Protocol        (LPP) messages.    -   Clause 26. The UE of any of clauses 15 to 25, wherein the at        least one processor is further configured to: transmit, via the        at least one transceiver, a model failure report indicating that        the first positioning model has failed.    -   Clause 27. The UE of clause 26, wherein: the model failure        report is transmitted in response to determining that the number        of positioning model error instances satisfy the positioning        model failure criteria; receiving a model failure report        request; or any combination thereof.    -   Clause 28. The UE of clause 27, wherein the model failure report        indicates: a first model identifier associated with the first        positioning model; a second model identifier associated with a        second positioning model applied to the RFFP measurements to        obtain the second position estimate; an identification of one or        more positioning techniques used to obtain the second position        estimate; one or more timestamps associated with one or more        positioning model error instances of the positioning model error        instances; a time span associated with determining the one or        more positioning model error instances; one or more position        uncertainty error values associated with the one or more        positioning model error instances; channel condition parameters        associated with the one or more positioning model error        instances; or any combination thereof.    -   Clause 29. A user equipment (UE), comprising: means for        determining that a positioning model error instance has occurred        during a positioning occasion based on 1) a position uncertainty        associated with a first position estimate satisfying positioning        uncertainty error criteria, wherein the first position estimate        is obtained during the positioning occasion by applying a first        positioning model to radio frequency fingerprint (RFFP)        measurements, 2) a positioning mismatch between the first        position estimate of the UE and a second position estimate of        the UE satisfying position mismatch error criteria, wherein the        second position estimate of the UE is obtained during the        positioning occasion by performing a positioning technique that        does not use the first positioning model, or 3) any combination        thereof; and means for determining that the first positioning        model has failed based on a number of positioning model error        instances satisfying positioning model failure criteria.    -   Clause 30. The UE of clause 29, further comprising: means for        deactivating the first positioning model in response to        determining that the number of positioning model error instances        satisfies the positioning model failure criteria, and means for        activating a fallback positioning technique that does not use        the first positioning model in further positioning occasions in        response to determining that the number of positioning model        error instances satisfies the positioning model failure        criteria.    -   Clause 31. The UE of clause 30, further comprising: means for        receiving an indication of a type of positioning technique to be        used as the fallback positioning technique; means for receiving        one or more parameters of the fallback positioning technique;        means for configuring the UE with the type of positioning        technique used for the fallback positioning technique based on a        pre-configuration of the type of positioning technique to be        used for the fallback positioning technique at the UE; means for        configuring the UE with the one or more parameters of the        fallback positioning technique based on a pre-configuration of        the one or more parameters of the fallback positioning technique        at the UE; or any combination thereof.    -   Clause 32. The UE of clause 31, wherein: the type of positioning        technique used for the fallback positioning technique is        received via a first set of LPP messages; the one or more        parameters of the fallback positioning technique are received        via a second set of LPP messages; or any combination thereof.    -   Clause 33. The UE of any of clauses 30 to 32, wherein the        fallback positioning technique comprises: a further RFFP        technique using a second positioning model; a Global Navigation        Satellite System (GNSS) positioning technique; a New Radio (NR)        positioning technique; or any combination thereof.    -   Clause 34. The UE of any of clauses 30 to 33, further        comprising: means for reactivating the first positioning model        based on expiration of a time threshold since deactivating the        first positioning model, expiration of a time threshold since        activating the fallback positioning technique, using the        fallback positioning technique for a threshold number of        positioning occasions, receiving a request to reactivate the        first positioning model, or any combination thereof.    -   Clause 35. The UE of any of clauses 29 to 34, wherein the        positioning model failure criteria comprises: a total number of        positioning model error instances; a number of positioning model        error instances occurring over a time duration; or any        combination thereof.    -   Clause 36. The UE of any of clauses 29 to 35, wherein the        positioning uncertainty error criteria comprises: the position        uncertainty associated with the first position estimate        exceeding a position uncertainty threshold.    -   Clause 37. The UE of any of clauses 29 to 36, wherein the        position mismatch error criteria comprises: a position        difference between the first position estimate and the second        position estimate exceeding a position difference threshold.    -   Clause 38. The UE of any of clauses 29 to 37, further        comprising: means for receiving one or more parameters        indicating the positioning model failure criteria; means for        configuring the one or more parameters of the positioning model        failure criteria based on a pre-configuration of the one or more        parameters of the positioning model failure criteria at the UE;        or a combination thereof.    -   Clause 39. The UE of clause 38, wherein: the one or more        parameters indicating the positioning model failure criteria are        received via a set of Long-Term Evolution Positioning Protocol        (LPP) messages.    -   Clause 40. The UE of any of clauses 29 to 39, further        comprising: means for transmitting a model failure report        indicating that the first positioning model has failed.    -   Clause 41. The UE of clause 40, wherein: the model failure        report is transmitted in response to determining that the number        of positioning model error instances satisfy the positioning        model failure criteria; receiving a model failure report        request; or any combination thereof.    -   Clause 42. The UE of clause 41, wherein the model failure report        indicates: a first model identifier associated with the first        positioning model; a second model identifier associated with a        second positioning model applied to the RFFP measurements to        obtain the second position estimate; an identification of one or        more positioning techniques used to obtain the second position        estimate; one or more timestamps associated with one or more        positioning model error instances of the positioning model error        instances; a time span associated with determining the one or        more positioning model error instances; one or more position        uncertainty error values associated with the one or more        positioning model error instances; channel condition parameters        associated with the one or more positioning model error        instances; or any combination thereof.    -   Clause 43. A non-transitory computer-readable medium storing        computer-executable instructions that, when executed by a user        equipment (UE), cause the UE to: determine that a positioning        model error instance has occurred during a positioning occasion        based on 1) a position uncertainty associated with a first        position estimate satisfying positioning uncertainty error        criteria, wherein the first position estimate is obtained during        the positioning occasion by applying a first positioning model        to radio frequency fingerprint (RFFP) measurements, 2) a        positioning mismatch between the first position estimate of the        UE and a second position estimate of the UE satisfying position        mismatch error criteria, wherein the second position estimate of        the UE is obtained during the positioning occasion by performing        a positioning technique that does not use the first positioning        model, or 3) any combination thereof; and determine that the        first positioning model has failed based on a number of        positioning model error instances satisfying positioning model        failure criteria.    -   Clause 44. The non-transitory computer-readable medium of clause        43, further comprising computer-executable instructions that,        when executed by the UE, cause the UE to: in response to        determining that the number of positioning model error instances        satisfies the positioning model failure criteria, deactivate the        first positioning model, and activate a fallback positioning        technique that does not use the first positioning model in        further positioning occasions.    -   Clause 45. The non-transitory computer-readable medium of clause        44, further comprising computer-executable instructions that,        when executed by the UE, cause the UE to: receive an indication        of a type of positioning technique to be used as the fallback        positioning technique; receive one or more parameters of the        fallback positioning technique; configure the UE with the type        of positioning technique used for the fallback positioning        technique based on a pre-configuration of the type of        positioning technique to be used for the fallback positioning        technique at the UE; configure the UE with the one or more        parameters of the fallback positioning technique based on a        pre-configuration of the one or more parameters of the fallback        positioning technique at the UE; or any combination thereof.    -   Clause 46. The non-transitory computer-readable medium of clause        45, wherein: the type of positioning technique used for the        fallback positioning technique is received via a first set of        LPP messages; the one or more parameters of the fallback        positioning technique are received via a second set of LPP        messages; or any combination thereof.    -   Clause 47. The non-transitory computer-readable medium of any of        clauses 44 to 46, wherein the fallback positioning technique        comprises: a further RFFP technique using a second positioning        model; a Global Navigation Satellite System (GNSS) positioning        technique; a New Radio (NR) positioning technique; or any        combination thereof.    -   Clause 48. The non-transitory computer-readable medium of any of        clauses 44 to 47, further comprising computer-executable        instructions that, when executed by the UE, cause the UE to:        reactivate the first positioning model based on expiration of a        time threshold since deactivating the first positioning model,        expiration of a time threshold since activating the fallback        positioning technique, using the fallback positioning technique        for a threshold number of positioning occasions, receiving a        request to reactivate the first positioning model, or any        combination thereof.    -   Clause 49. The non-transitory computer-readable medium of any of        clauses 43 to 48, wherein the positioning model failure criteria        comprises: a total number of positioning model error instances;        a number of positioning model error instances occurring over a        time duration; or any combination thereof.    -   Clause 50. The non-transitory computer-readable medium of any of        clauses 43 to 49, wherein the positioning uncertainty error        criteria comprises: the position uncertainty associated with the        first position estimate exceeding a position uncertainty        threshold.    -   Clause 51. The non-transitory computer-readable medium of any of        clauses 43 to 50, wherein the position mismatch error criteria        comprises: a position difference between the first position        estimate and the second position estimate exceeding a position        difference threshold.    -   Clause 52. The non-transitory computer-readable medium of any of        clauses 43 to 51, further comprising computer-executable        instructions that, when executed by the UE, cause the UE to:        receive one or more parameters indicating the positioning model        failure criteria; configure the one or more parameters of the        positioning model failure criteria based on a pre-configuration        of the one or more parameters of the positioning model failure        criteria at the UE; or a combination thereof.    -   Clause 53. The non-transitory computer-readable medium of clause        52, wherein: the one or more parameters indicating the        positioning model failure criteria are received via a set of        Long-Term Evolution Positioning Protocol (LPP) messages.    -   Clause 54. The non-transitory computer-readable medium of any of        clauses 43 to 53, further comprising computer-executable        instructions that, when executed by the UE, cause the UE to:        transmit a model failure report indicating that the first        positioning model has failed.    -   Clause 55. The non-transitory computer-readable medium of clause        54, wherein: the model failure report is transmitted in response        to determining that the number of positioning model error        instances satisfy the positioning model failure criteria;        receiving a model failure report request; or any combination        thereof.    -   Clause 56. The non-transitory computer-readable medium of clause        55, wherein the model failure report indicates: a first model        identifier associated with the first positioning model; a second        model identifier associated with a second positioning model        applied to the RFFP measurements to obtain the second position        estimate; an identification of one or more positioning        techniques used to obtain the second position estimate; one or        more timestamps associated with one or more positioning model        error instances of the positioning model error instances; a time        span associated with determining the one or more positioning        model error instances; one or more position uncertainty error        values associated with the one or more positioning model error        instances; channel condition parameters associated with the one        or more positioning model error instances; or any combination        thereof.

Those of skill in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those of skill in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an ASIC, a field-programmable gate array (FPGA), or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices,for example, a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The methods, sequences and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art. An example storage medium is coupled to the processor such thatthe processor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal (e.g., UE). In thealternative, the processor and the storage medium may reside as discretecomponents in a user terminal.

In one or more example aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects of thedisclosure, it should be noted that various changes and modificationscould be made herein without departing from the scope of the disclosureas defined by the appended claims. The functions, steps and/or actionsof the method claims in accordance with the aspects of the disclosuredescribed herein need not be performed in any particular order.Furthermore, although elements of the disclosure may be described orclaimed in the singular, the plural is contemplated unless limitation tothe singular is explicitly stated.

What is claimed is:
 1. A method of wireless communication performed by auser equipment (UE), comprising: determining that a positioning modelerror instance has occurred during a positioning occasion based on aposition uncertainty associated with a first position estimatesatisfying positioning uncertainty error criteria, wherein the firstposition estimate is obtained during the positioning occasion byapplying a first positioning model to radio frequency fingerprint (RFFP)measurements, a positioning mismatch between the first position estimateof the UE and a second position estimate of the UE satisfying positionmismatch error criteria, wherein the second position estimate of the UEis obtained during the positioning occasion by performing a positioningtechnique that does not use the first positioning model, or anycombination thereof, and determining that the first positioning modelhas failed based on a number of positioning model error instancessatisfying positioning model failure criteria.
 2. The method of claim 1,further comprising: in response to determining that the number ofpositioning model error instances satisfies the positioning modelfailure criteria, deactivating the first positioning model, andactivating a fallback positioning technique that does not use the firstpositioning model in further positioning occasions.
 3. The method ofclaim 2, further comprising: receiving an indication of a type ofpositioning technique to be used as the fallback positioning technique;receiving one or more parameters of the fallback positioning technique;configuring the UE with the type of positioning technique used for thefallback positioning technique based on a pre-configuration of the typeof positioning technique to be used for the fallback positioningtechnique at the UE; configuring the UE with the one or more parametersof the fallback positioning technique based on a pre-configuration ofthe one or more parameters of the fallback positioning technique at theUE; or any combination thereof.
 4. The method of claim 3, wherein: thetype of positioning technique used for the fallback positioningtechnique is received via a first set of LPP messages; the one or moreparameters of the fallback positioning technique are received via asecond set of LPP messages; or any combination thereof.
 5. The method ofclaim 2, wherein the fallback positioning technique comprises: a furtherRFFP technique using a second positioning model; a Global NavigationSatellite System (GNSS) positioning technique; a New Radio (NR)positioning technique; or any combination thereof.
 6. The method ofclaim 2, further comprising: reactivating the first positioning modelbased on expiration of a time threshold since deactivating the firstpositioning model, expiration of a time threshold since activating thefallback positioning technique, using the fallback positioning techniquefor a threshold number of positioning occasions, receiving a request toreactivate the first positioning model, or any combination thereof. 7.The method of claim 1, wherein the positioning model failure criteriacomprises: a total number of positioning model error instances; a numberof positioning model error instances occurring over a time duration; orany combination thereof.
 8. The method of claim 1, wherein thepositioning uncertainty error criteria comprises: the positionuncertainty associated with the first position estimate exceeding aposition uncertainty threshold.
 9. The method of claim 1, wherein theposition mismatch error criteria comprises: a position differencebetween the first position estimate and the second position estimateexceeding a position difference threshold.
 10. The method of claim 1,further comprising: receiving one or more parameters indicating thepositioning model failure criteria; configuring the one or moreparameters of the positioning model failure criteria based on apre-configuration of the one or more parameters of the positioning modelfailure criteria at the UE; or a combination thereof.
 11. The method ofclaim 10, wherein: the one or more parameters indicating the positioningmodel failure criteria are received via a set of Long-Term EvolutionPositioning Protocol (LPP) messages.
 12. The method of claim 1, furthercomprising: transmitting a model failure report indicating that thefirst positioning model has failed.
 13. The method of claim 12, wherein:the model failure report is transmitted in response to determining thatthe number of positioning model error instances satisfy the positioningmodel failure criteria; receiving a model failure report request; or anycombination thereof.
 14. The method of claim 13, wherein the modelfailure report indicates: a first model identifier associated with thefirst positioning model; a second model identifier associated with asecond positioning model applied to the RFFP measurements to obtain thesecond position estimate; an identification of one or more positioningtechniques used to obtain the second position estimate; one or moretimestamps associated with one or more positioning model error instancesof the positioning model error instances; a time span associated withdetermining the one or more positioning model error instances; one ormore position uncertainty error values associated with the one or morepositioning model error instances; channel condition parametersassociated with the one or more positioning model error instances; orany combination thereof.
 15. A user equipment (UE), comprising: amemory; at least one transceiver; and at least one processorcommunicatively coupled to the memory and the at least one transceiver,the at least one processor configured to: determine that a positioningmodel error instance has occurred during a positioning occasion based ona position uncertainty associated with a first position estimatesatisfying positioning uncertainty error criteria, wherein the firstposition estimate is obtained during the positioning occasion byapplying a first positioning model to radio frequency fingerprint (RFFP)measurements, a positioning mismatch between the first position estimateof the UE and a second position estimate of the UE satisfying positionmismatch error criteria, wherein the second position estimate of the UEis obtained during the positioning occasion by performing a positioningtechnique that does not use the first positioning model, or anycombination thereof, and determine that the first positioning model hasfailed based on a number of positioning model error instances satisfyingpositioning model failure criteria.
 16. The UE of claim 15, wherein theat least one processor is further configured to: in response todetermining that the number of positioning model error instancessatisfies the positioning model failure criteria, deactivate the firstpositioning model, and activate a fallback positioning technique thatdoes not use the first positioning model in further positioningoccasions.
 17. The UE of claim 16, wherein the at least one processor isfurther configured to: receive, via the at least one transceiver, anindication of a type of positioning technique to be used as the fallbackpositioning technique; receive, via the at least one transceiver, one ormore parameters of the fallback positioning technique; configure the UEwith the type of positioning technique used for the fallback positioningtechnique based on a pre-configuration of the type of positioningtechnique to be used for the fallback positioning technique at the UE;configure the UE with the one or more parameters of the fallbackpositioning technique based on a pre-configuration of the one or moreparameters of the fallback positioning technique at the UE; or anycombination thereof.
 18. The UE of claim 17, wherein: the type ofpositioning technique used for the fallback positioning technique isreceived via a first set of LPP messages; the one or more parameters ofthe fallback positioning technique are received via a second set of LPPmessages; or any combination thereof.
 19. The UE of claim 16, whereinthe fallback positioning technique comprises: a further RFFP techniqueusing a second positioning model; a Global Navigation Satellite System(GNSS) positioning technique; a New Radio (NR) positioning technique; orany combination thereof.
 20. The UE of claim 16, wherein the at leastone processor is further configured to: reactivate the first positioningmodel based on expiration of a time threshold since deactivating thefirst positioning model, expiration of a time threshold since activatingthe fallback positioning technique, using the fallback positioningtechnique for a threshold number of positioning occasions, receiving,via the at least one transceiver, a request to reactivate the firstpositioning model, or any combination thereof.
 21. The UE of claim 15,wherein the positioning model failure criteria comprises: a total numberof positioning model error instances; a number of positioning modelerror instances occurring over a time duration; or any combinationthereof.
 22. The UE of claim 15, wherein the positioning uncertaintyerror criteria comprises: the position uncertainty associated with thefirst position estimate exceeding a position uncertainty threshold. 23.The UE of claim 15, wherein the position mismatch error criteriacomprises: a position difference between the first position estimate andthe second position estimate exceeding a position difference threshold.24. The UE of claim 15, wherein the at least one processor is furtherconfigured to: receive, via the at least one transceiver, one or moreparameters indicating the positioning model failure criteria; configurethe one or more parameters of the positioning model failure criteriabased on a pre-configuration of the one or more parameters of thepositioning model failure criteria at the UE; or a combination thereof.25. The UE of claim 24, wherein: the one or more parameters indicatingthe positioning model failure criteria are received via a set ofLong-Term Evolution Positioning Protocol (LPP) messages.
 26. The UE ofclaim 15, wherein the at least one processor is further configured to:transmit, via the at least one transceiver, a model failure reportindicating that the first positioning model has failed.
 27. The UE ofclaim 26, wherein: the model failure report is transmitted in responseto determining that the number of positioning model error instancessatisfy the positioning model failure criteria; receiving a modelfailure report request; or any combination thereof.
 28. The UE of claim27, wherein the model failure report indicates: a first model identifierassociated with the first positioning model; a second model identifierassociated with a second positioning model applied to the RFFPmeasurements to obtain the second position estimate; an identificationof one or more positioning techniques used to obtain the second positionestimate; one or more timestamps associated with one or more positioningmodel error instances of the positioning model error instances; a timespan associated with determining the one or more positioning model errorinstances; one or more position uncertainty error values associated withthe one or more positioning model error instances; channel conditionparameters associated with the one or more positioning model errorinstances; or any combination thereof.
 29. A user equipment (UE),comprising: means for determining that a positioning model errorinstance has occurred during a positioning occasion based on a positionuncertainty associated with a first position estimate satisfyingpositioning uncertainty error criteria, wherein the first positionestimate is obtained during the positioning occasion by applying a firstpositioning model to radio frequency fingerprint (RFFP) measurements, apositioning mismatch between the first position estimate of the UE and asecond position estimate of the UE satisfying position mismatch errorcriteria, wherein the second position estimate of the UE is obtainedduring the positioning occasion by performing a positioning techniquethat does not use the first positioning model, or any combinationthereof, and means for determining that the first positioning model hasfailed based on a number of positioning model error instances satisfyingpositioning model failure criteria.
 30. A non-transitorycomputer-readable medium storing computer-executable instructions that,when executed by a user equipment (UE), cause the UE to: determine thata positioning model error instance has occurred during a positioningoccasion based on a position uncertainty associated with a firstposition estimate satisfying positioning uncertainty error criteria,wherein the first position estimate is obtained during the positioningoccasion by applying a first positioning model to radio frequencyfingerprint (RFFP) measurements, a positioning mismatch between thefirst position estimate of the UE and a second position estimate of theUE satisfying position mismatch error criteria, wherein the secondposition estimate of the UE is obtained during the positioning occasionby performing a positioning technique that does not use the firstpositioning model, or any combination thereof, and determine that thefirst positioning model has failed based on a number of positioningmodel error instances satisfying positioning model failure criteria.